Answer the genral Pharmacology part for my MBBS professional exams and include relevant diagrams
General Pharmacology - MBBS Professional Exam Answers
1. Advantages and Disadvantages of Different Routes of Drug Administration
Oral Route
Sublingual (SL) Route
Rectal Route
Intravenous (IV) Route
Intramuscular (IM) Route
Subcutaneous (SC) Route
Inhalation
Transdermal Route
ROUTE COMPARISON TABLE
─────────────────────────────────────────────────────────
Route | Onset | Bioavail. | Examples
─────────────────────────────────────────────────────────
IV | Seconds | 100% | Morphine, Lignocaine
IM | 10-30 min | ~75-100% | Penicillin, Vaccines
SC | 15-30 min | ~75-100% | Insulin, Heparin
Oral | 30-90 min | Variable | Aspirin, Metformin
Sublingual | 1-2 min | High | GTN, Buprenorphine
Rectal | 5-30 min | ~50% | Diazepam, Paracetamol
Transdermal | Hours | Moderate | GTN, Scopolamine
Inhalation | Minutes | High | Salbutamol, Steroids
─────────────────────────────────────────────────────────
2. Generic and Chemical Name of Drugs
| Concept | Definition | Example |
|---|---|---|
| Chemical name | Full IUPAC name describing molecular structure | N-(4-hydroxyphenyl)acetamide |
| Generic (Non-proprietary) name | Approved official name (INN - International Nonproprietary Name) | Paracetamol / Acetaminophen |
| Brand (Proprietary) name | Manufacturer's trade name | Crocin, Tylenol |
| Chemical Name | Generic Name | Brand Name |
|---|---|---|
| 2-Acetoxybenzoic acid | Aspirin | Ecosprin |
| 7-Chloro-1,3-dihydro-1-methyl-5-phenyl-2H-benzo[e]-1,4-diazepin-2-one | Diazepam | Valium |
| 1-[p-chloro-α-(2-methylbenzyl)benzyl]imidazole | Clotrimazole | Candid |
3. Special Drug Delivery Systems Including Transdermal Drug Delivery System (TDDS)
Special Drug Delivery Systems:
- Drug released slowly over 8-12 hours
- Reduces dosing frequency, maintains steady plasma levels
- Example: Nifedipine SR, Metformin SR
- Coated to resist gastric acid; dissolves in alkaline intestinal pH
- Protects GI mucosa from irritant drugs (e.g., Aspirin EC)
- Protects acid-labile drugs (e.g., Omeprazole)
STRUCTURE OF A TRANSDERMAL PATCH
┌─────────────────────────────────────┐
│ Backing layer (occlusive film) │
├─────────────────────────────────────┤
│ Drug reservoir (gel/matrix) │
├─────────────────────────────────────┤
│ Rate-controlling membrane │
├─────────────────────────────────────┤
│ Contact adhesive layer │
├─────────────────────────────────────┤
│ Release liner (peeled before use) │
└─────────────────────────────────────┘
↓↓ Drug permeates skin ↓↓
[Stratum corneum → Dermis → Capillaries]
- High lipid solubility
- Low molecular weight (<500 Da)
- Potent (low dose required)
- Non-irritating to skin
4. Management of Anaphylactic Shock
Immediate Steps:
- Stop the offending agent
- Call for help; place patient supine with legs elevated
- Adrenaline (Epinephrine) 0.5 mg IM (1:1000 solution) into anterolateral thigh - DRUG OF CHOICE
- Repeat every 5 minutes if needed
- Mechanism: α1 - vasoconstriction (reverses hypotension); β1 - increases heart rate/contractility; β2 - bronchodilation + inhibits mast cell degranulation
- Oxygen - high flow (10-15 L/min via face mask)
- IV access - infuse normal saline rapidly for fluid resuscitation
- Antihistamine - Chlorphenamine 10 mg IV (H1 blocker)
- Corticosteroid - Hydrocortisone 200 mg IV (prevents late-phase reaction, takes 4-6 hours)
- Salbutamol nebulization if bronchospasm persists
ANAPHYLAXIS MANAGEMENT SUMMARY
────────────────────────────────────────────────
IMMEDIATE: Adrenaline 0.5 mg IM (1:1000)
↓
OXYGEN + IV fluids (0.9% NaCl bolus)
↓
ANTIHISTAMINE: Chlorphenamine 10 mg IV
↓
STEROID: Hydrocortisone 200 mg IV
↓
BRONCHOSPASM: Salbutamol nebulizer
↓
REFRACTORY: IV Adrenaline infusion
Glucagon (if on beta-blockers)
────────────────────────────────────────────────
5. Teratogenic Drugs
FDA Pregnancy Categories (Classic Classification):
- Category A: Safe (folic acid, levothyroxine in controlled doses)
- Category B: Animal studies safe, no adequate human studies (e.g., Metformin)
- Category C: Animal studies show risk, no adequate human studies (e.g., Aspirin, Furosemide)
- Category D: Evidence of fetal risk but benefits may outweigh risks (e.g., Phenytoin, Valproate)
- Category X: Contraindicated - risks outweigh benefits (e.g., Thalidomide, Isotretinoin, Warfarin, Methotrexate)
Important Teratogenic Drugs:
| Drug | Teratogenic Effect |
|---|---|
| Thalidomide | Phocomelia (limb reduction defects) |
| Valproic acid | Neural tube defects (spina bifida), facial defects |
| Phenytoin | Fetal hydantoin syndrome (cleft palate, growth retardation, nail hypoplasia) |
| Warfarin (1st trimester) | Warfarin embryopathy (nasal hypoplasia, stippled epiphyses) |
| Tetracyclines | Yellow discoloration and hypoplasia of teeth and bones |
| Isotretinoin (Vit A) | CNS, cardiac, and craniofacial defects |
| ACE Inhibitors (2nd/3rd trimester) | Renal tubular dysplasia, oligohydramnios |
| Methotrexate | Folic acid antagonist → neural tube defects, limb anomalies |
| Diethylstilbestrol (DES) | Vaginal clear cell carcinoma in female offspring |
| Misoprostol | Möbius syndrome |
| Carbamazepine | Neural tube defects |
| Lithium | Ebstein's cardiac anomaly |
| Aminoglycosides | Ototoxicity (8th nerve damage) |
6. Drug Antagonism
Types:
- Antagonist competes with agonist for same receptor binding site
- Can be overcome by increasing agonist concentration
- Shifts dose-response curve to RIGHT (parallel shift), Emax unchanged
- Example: Atropine vs Acetylcholine; Naloxone vs Morphine; Propranolol vs Adrenaline
- Antagonist binds at same or different site but cannot be displaced
- Emax reduced (ceiling effect decreased), right shift
- Example: Phenoxybenzamine (irreversible α-blocker)
- Drug with lower intrinsic activity competes with full agonist
- Example: Buprenorphine vs Morphine
- Two drugs act on different receptors but produce opposing effects on same physiological endpoint
- Example: Adrenaline (bronchodilation) antagonizes Histamine (bronchoconstriction)
- Direct chemical interaction neutralizes the drug
- Example: Protamine neutralizes Heparin; Chelation therapy (EDTA for heavy metals)
- One drug alters absorption, distribution, or metabolism of another
- Example: Enzyme inducers (Rifampicin, Phenobarbitone) reduce plasma levels of co-administered drugs
DOSE-RESPONSE CURVES IN ANTAGONISM
Effect
|
Emax ├─── ─ ─ ─ ─── ─ ─ ─ ─ ─ ─ ─ ← Agonist alone
│ /
│ /
│ Competitive Non-competitive
│ antagonist antagonist
│ /── /── (Emax reduced)
└──────────────────────────────▶ Log [Dose]
Competitive: Parallel right shift, same Emax
Non-competitive: Right shift + Emax reduced
7. Plasma Protein Binding
- Bound fraction (to plasma proteins - pharmacologically inactive, non-diffusible reservoir)
- Free/unbound fraction (pharmacologically ACTIVE, able to cross membranes)
Proteins involved:
- Albumin - binds acidic drugs (Warfarin, Phenytoin, Aspirin, Furosemide)
- α1-acid glycoprotein (AAG) - binds basic drugs (Lidocaine, Propranolol, Quinidine)
- Globulins - bind hormones, vitamins, iron, cortisol
Clinical Significance:
| Situation | Effect |
|---|---|
| Hypoalbuminaemia (liver disease, nephrotic syndrome) | ↑ Free drug → Toxicity at normal doses |
| Drug displacement from binding sites | Transient ↑ free drug (quickly cleared) |
| Neonates | Low albumin → Higher free drug fraction |
- Crosses blood-brain barrier
- Is filtered at glomerulus
- Is metabolized by liver
- Exerts pharmacological effect
- Is measured by volume of distribution
8. First Pass Metabolism
Pathway:
ORAL DRUG → GI Lumen → Gut Wall (CYP3A4) → Portal Vein
↓
Liver (CYP450 enzymes)
↓
SYSTEMIC CIRCULATION (reduced amount)
Result:
- Only a fraction of the administered dose reaches systemic circulation
- This reduces bioavailability
Drugs with High First Pass Effect (>70% extraction):
- Morphine (oral bioavailability ~25%)
- Propranolol (oral bioavailability ~25%)
- Lidocaine (given IV only for arrhythmia - ~3% oral bioavailability)
- GTN (oral bioavailability <1%)
- Aspirin
- Salbutamol (significant)
- Testosterone (extensive first pass → use methyltestosterone or patches)
Ways to Bypass First Pass:
- Sublingual (GTN tablet)
- Transdermal (GTN patch)
- Rectal (partial bypass ~50%)
- Parenteral (IM, IV, SC)
- Inhalation
Factors affecting first pass:
- Blood flow to liver (reduced in liver disease → ↑ bioavailability of high extraction drugs)
- Enzyme induction/inhibition
- Gut wall metabolism (CYP3A4)
9. Bioavailability
Bioavailability (F) = AUC oral / AUC IV × 100%
AUC = Area Under the Plasma Concentration-Time Curve
PLASMA CONCENTRATION - TIME CURVE
Plasma
conc. ┤
(Cp) │ ╭─────╮
│ / \ ← IV (AUC = 100%)
│ / \
│ / ╭─────╮
│ / / \ ← Oral (AUC < 100%)
│ / / \
└───┴─────────────────▶ Time
Tmax
Absolute vs Relative Bioavailability:
- Absolute: Compared to IV (100%) - true F value
- Relative: Compared to another oral formulation (reference standard)
Factors Affecting Bioavailability:
- Route of administration (IV = 100%)
- First pass metabolism (reduces oral bioavailability)
- Gut motility (faster = less absorption)
- Food (can increase or decrease)
- Drug formulation (particle size, excipients)
- Drug solubility and dissolution
- Liver/gut wall enzyme activity
- Drug-drug interactions (e.g., antacids reduce absorption of fluoroquinolones)
| Route | Approximate Bioavailability |
|---|---|
| IV | 100% |
| IM | 75-100% |
| Oral | 5-100% (variable) |
| Sublingual | 50-75% (bypasses first pass) |
| Rectal | ~50% |
| Transdermal | Variable (low to moderate) |
10. Why is Omeprazole Given on an Empty Stomach in the Morning?
Mechanism of Action of Omeprazole:
- Omeprazole is a Proton Pump Inhibitor (PPI)
- It is a prodrug - converted to active sulphenamide in acidic canalicular pH of parietal cells
- Active form irreversibly inhibits H+/K+ ATPase (the proton pump) on the luminal surface of parietal cells
Why empty stomach?
- Omeprazole is unstable in gastric acid (degrades at low pH)
- Taken as enteric-coated capsule to protect from gastric acid
- The enteric coating dissolves in the small intestine (alkaline pH)
- Omeprazole only inhibits pumps that are actively secreting acid
- Maximum number of active proton pumps are present after fasting (especially overnight fast)
- After meals, many pumps are already cycling/synthesizing
- Fasting → pumps recruited to canalicular membrane → ready to be inhibited
- After overnight fast, most pumps are active in the morning
- A meal after taking omeprazole stimulates acid secretion and activates the pumps
- Omeprazole is then present in bloodstream to inhibit these active pumps
- Optimal: Take 30-60 minutes BEFORE breakfast
SEQUENCE FOR MAXIMUM EFFECT:
Overnight fast → Proton pumps recruited
↓
Take Omeprazole (30-60 min before breakfast)
↓
Omeprazole absorbed from small intestine
↓
Circulates to parietal cell → converted to sulphenamide
↓
Eat breakfast → Stimulates acid secretion → Pumps activated
↓
Active sulphenamide irreversibly binds active H+/K+ ATPase
↓
Maximum acid suppression achieved
11. Zero Order and First Order Kinetics
First Order Kinetics (Exponential):
- A constant FRACTION (%) of the drug is eliminated per unit time
- Rate of elimination is proportional to drug concentration
- At higher concentration → faster elimination (but same fraction)
- Produces a straight line on semi-log plot
- Has a constant half-life
- Most drugs at therapeutic concentrations follow first order kinetics
FIRST ORDER: Cp vs Time (Semi-log)
Log Cp | ─────────
│ ────────────
│ ────────
└────────────────────────────────▶ Time
(STRAIGHT LINE)
Zero Order Kinetics (Linear):
- A constant AMOUNT of drug is eliminated per unit time
- Occurs when elimination mechanisms are saturated (capacity-limited)
- Rate does NOT depend on concentration (fixed amount per hour)
- Produces a straight line on linear plot
- Half-life is NOT constant - increases as concentration rises
- Small dose changes → disproportionately large changes in plasma level (DANGEROUS)
ZERO ORDER: Cp vs Time (Linear)
Cp | ────────────────────────────────
│ ─────────
└────────────────────────────────────────────▶ Time
(STRAIGHT LINE on linear plot)
Drugs showing zero order at therapeutic doses:
- Phenytoin (classic example - "saturation kinetics")
- Alcohol (Ethanol) - 10 g/hour metabolized regardless of concentration
- Aspirin at high (anti-inflammatory) doses
Michaelis-Menten Kinetics:
v = Vmax × C / (Km + C)
Vmax = maximum elimination rate
Km = concentration at half-Vmax (Michaelis constant)
C = drug concentration
When C << Km → First order
When C >> Km → Zero order
12. Plasma Half Life (t½)
t½ = 0.693 × Vd / CL
Vd = Volume of distribution
CL = Clearance
0.693 = ln2 (natural log of 2)
Significance:
- Time to reach steady state: ~4-5 half-lives after starting regular dosing
- Time for drug elimination: ~4-5 half-lives for 97% elimination
- Dosing interval: Usually equal to one half-life
- Loading dose: May be needed if t½ is long (e.g., digoxin)
HALF-LIFE CONCEPT
Plasma 100 ─────────────────────────────
Conc (%) │
│
50─┤ ─────────────────────
│
25─┤ ──────────
│
12.5┤ ─────
└──┬──────────┬──────────┬──────▶ Time
t½ 2t½ 3t½
ACCUMULATION TO STEADY STATE
% Steady │
state │ ─────────── 100%
achieved │ ───────
│ ───────
│ ──────
└──────────────────────────────▶
1 2 3 4 5 (number of t½)
Clinical Examples:
| Drug | t½ | Clinical Implication |
|---|---|---|
| Digoxin | 36 hours | Once daily dosing; takes ~1 week to steady state |
| Aspirin | 15-20 min (metabolite 4-6 hr) | |
| Warfarin | 36-42 hours | INR takes 3-4 days to stabilize |
| Penicillin G | 30 min | 4-6 hourly dosing needed |
| Amiodarone | 40-55 days | Very long - drug interaction concerns |
| Thiopentone | Short distribution t½ (short action) but long elimination t½ | Cumulation on repeated dosing |
13. Therapeutic Drug Monitoring (TDM)
Therapeutic Window:
THERAPEUTIC WINDOW
Plasma │ ───────────────────── ← TOXIC LEVEL
conc. │ / Toxic range
│──────────/────────────────────── ← MTC (Minimum Toxic Conc.)
│ / THERAPEUTIC WINDOW
│────────/──────────────────────── ← MEC (Minimum Effective Conc.)
│ / Subtherapeutic
└──────────────────────────────────▶ Time
Indications for TDM:
- Narrow therapeutic index drugs (small difference between effective and toxic dose)
- Non-linear pharmacokinetics (Phenytoin)
- High inter-individual variability (due to genetics, disease)
- Serious adverse effects (aminoglycosides - nephrotoxicity/ototoxicity)
- Suspected non-compliance
- Suspected toxicity
- Altered drug handling (renal/hepatic disease)
Drugs routinely monitored:
| Drug | Therapeutic Range | Reason |
|---|---|---|
| Digoxin | 0.8-2 ng/mL | Narrow TI, toxicity common |
| Phenytoin | 10-20 μg/mL | Zero order kinetics, toxicity |
| Lithium | 0.6-1.2 mEq/L | Narrow TI, serious toxicity |
| Aminoglycosides | Peak: 5-10 μg/mL; Trough: <2 μg/mL | Nephro/ototoxicity |
| Vancomycin | Trough: 10-20 μg/mL | Toxicity |
| Carbamazepine | 4-12 μg/mL | NTI |
| Valproate | 50-100 μg/mL | NTI |
| Cyclosporin | 100-400 ng/mL | Nephrotoxicity |
| Theophylline | 10-20 μg/mL | Narrow TI |
| Methotrexate | <1 μmol/L at 48 hrs | High-dose MTX toxicity |
14. Fixed Dose Combination (FDC)
Rationale / Advantages:
| Advantage | Example |
|---|---|
| Synergistic effect - enhanced efficacy | Co-trimoxazole (Trimethoprim + Sulfamethoxazole) |
| Reduced adverse effects (lower doses of each) | Levodopa + Carbidopa (Carbidopa prevents peripheral L-DOPA conversion, reducing nausea) |
| Improved compliance (fewer tablets) | Anti-TB regimens (HRZE), HIV HAART (Tenofovir + Emtricitabine + Efavirenz = Atripla) |
| Delay in drug resistance (anti-TB, HIV) | Anti-TB four-drug FDC |
| Convenience and cost-effectiveness | Antihypertensive combinations (Telmisartan + Amlodipine) |
Disadvantages:
- Cannot adjust dose of individual component
- If side effect occurs, can't identify which drug
- Pharmacokinetic incompatibility possible
- Regulatory challenges
Examples:
| FDC | Components | Use |
|---|---|---|
| Augmentin | Amoxicillin + Clavulanic acid | Antibacterial |
| Co-trimoxazole | Trimethoprim + Sulfamethoxazole | UTI, PCP |
| Sinemet | Levodopa + Carbidopa | Parkinson's disease |
| Lodoz | Bisoprolol + HCTZ | Hypertension |
| Combivir | Zidovudine + Lamivudine | HIV |
| Kaletra | Lopinavir + Ritonavir | HIV |
15. Clinical Trials
Phases of Clinical Trials:
PHASES OF CLINICAL TRIALS
─────────────────────────────────────────────────────────────────────────
PHASE 0 (Microdosing)
- <10 subjects (healthy volunteers)
- Sub-therapeutic dose (<1% of pharmacological dose)
- PK studies, target binding - NO therapeutic intent
─────────────────────────────────────────────────────────────────────────
PHASE I (First in Human)
- 20-100 HEALTHY VOLUNTEERS
- SAFETY, tolerance, PK, dose range finding
- Maximum tolerated dose determined
─────────────────────────────────────────────────────────────────────────
PHASE II (Pilot Efficacy)
- 100-300 PATIENTS with target disease
- EFFICACY and SAFETY
- Dose optimization
- Double-blind, placebo-controlled
─────────────────────────────────────────────────────────────────────────
PHASE III (Definitive Efficacy / Pivotal)
- 300-3000+ patients (multicenter, multinational)
- Compare with STANDARD TREATMENT
- Confirm efficacy, safety, ADR profile
- RANDOMIZED CONTROLLED TRIAL (RCT)
- Basis for regulatory approval (FDA, CDSCO)
─────────────────────────────────────────────────────────────────────────
PHASE IV (Post-marketing Surveillance)
- ENTIRE POPULATION using the drug post-approval
- Rare ADRs (not detected in Phase III), long-term safety
- PHARMACOVIGILANCE
- Drug may be withdrawn here (e.g., Rofecoxib/Vioxx)
─────────────────────────────────────────────────────────────────────────
Study Design Terms:
- Randomization: Participants randomly assigned to groups (eliminates selection bias)
- Blinding: Single-blind (patient unaware), Double-blind (patient + investigator unaware), Triple-blind (+ statistician)
- Placebo: Inert substance identical in appearance to test drug
- Crossover: Each patient receives both treatments sequentially
- Informed consent: Mandatory ethical requirement
16. Adverse Drug Reactions (ADR)
Classification (Rawlins & Thompson - Type A & B):
- Extension of pharmacological effect
- Most common (80% of ADRs)
- Example: Bleeding with Warfarin, Hypoglycemia with Insulin, Bradycardia with Propranolol
- Not related to pharmacological action
- Immunological (allergy) or genetic (idiosyncratic) mechanisms
- Example: Anaphylaxis with Penicillin, Aplastic anemia with Chloramphenicol, Malignant hyperthermia with Succinylcholine
Grading of ADR Severity:
- Mild: No therapy required, not disabling (e.g., mild nausea)
- Moderate: Requires change in therapy (e.g., rash)
- Severe: Life-threatening, requires hospitalization (e.g., Stevens-Johnson syndrome, anaphylaxis)
Pharmacovigilance:
- The science of monitoring drug safety post-marketing
- Yellow Card Scheme (UK) / MedWatch (USA) / PVPI (India) - systems for ADR reporting
- Naranjo Algorithm - tool to assess causality of ADR (Definite/Probable/Possible/Doubtful)
Common ADR Examples:
| Drug | ADR |
|---|---|
| ACE inhibitors | Dry cough (bradykinin accumulation) |
| Aminoglycosides | Nephrotoxicity, Ototoxicity |
| Chloramphenicol | Aplastic anemia, Grey baby syndrome |
| Metformin | Lactic acidosis |
| Statins | Myopathy, Rhabdomyolysis |
| Quinolones | Tendon rupture, QT prolongation |
| Clozapine | Agranulocytosis |
| Halothane | Hepatitis |
| Sulfonamides | Stevens-Johnson syndrome |
Study tip for exams: Topics 8, 9, 11, 12 often come together as linked questions on pharmacokinetics. ADR classification (Type A-F), anaphylaxis management, and teratogenic drugs are high-yield short answer/essay topics. Always draw labeled diagrams for dose-response curves, half-life curves, and the transdermal patch structure.
Create a PDF cheat sheet with all 16 General Pharmacology topics
ls -la /tmp/workspace/ 2>/dev/null || mkdir -p /tmp/workspace && echo "workspace ready"
mkdir -p /tmp/workspace/pharmacology-cheatsheet && cat > /tmp/workspace/pharmacology-cheatsheet/gen_pdf.py << 'PYEOF' from reportlab.lib.pagesizes import A4 from reportlab.lib import colors from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle from reportlab.lib.units import cm, mm from reportlab.platypus import (SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle, HRFlowable, KeepTogether, PageBreak) from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_JUSTIFY from reportlab.graphics.shapes import Drawing, Rect, String, Line, Polygon from reportlab.graphics import renderPDF from reportlab.platypus.flowables import Flowable import io # ─── COLOUR PALETTE ─────────────────────────────────────────────────────────── DARK_BLUE = colors.HexColor("#1A3A5C") MID_BLUE = colors.HexColor("#2E6DA4") LIGHT_BLUE = colors.HexColor("#D6E8F7") ACCENT_TEAL = colors.HexColor("#00897B") ACCENT_GREEN= colors.HexColor("#E8F5E9") WARN_RED = colors.HexColor("#C62828") WARN_YELLOW = colors.HexColor("#FFF9C4") WARN_BORDER = colors.HexColor("#F9A825") GRAY_BG = colors.HexColor("#F5F5F5") DARK_TEXT = colors.HexColor("#212121") TABLE_HEAD = colors.HexColor("#1A3A5C") TABLE_ALT = colors.HexColor("#EBF3FB") BOX_BG = colors.HexColor("#E3F2FD") BOX_BORDER = colors.HexColor("#1565C0") ORANGE_BG = colors.HexColor("#FFF3E0") ORANGE_BDR = colors.HexColor("#E65100") W, H = A4 # 595.27 x 841.89 pts # ─── STYLES ─────────────────────────────────────────────────────────────────── styles = getSampleStyleSheet() def sty(name, **kw): s = ParagraphStyle(name, **kw) return s TITLE = sty("TITLE", fontName="Helvetica-Bold", fontSize=20, textColor=colors.white, spaceAfter=4, alignment=TA_CENTER) SUBTITLE = sty("SUBTITLE", fontName="Helvetica", fontSize=11, textColor=colors.HexColor("#B0C4DE"), alignment=TA_CENTER, spaceAfter=2) H1 = sty("H1", fontName="Helvetica-Bold", fontSize=13, textColor=colors.white, spaceBefore=2, spaceAfter=4) H2 = sty("H2", fontName="Helvetica-Bold", fontSize=10, textColor=DARK_BLUE, spaceBefore=6, spaceAfter=3) H3 = sty("H3", fontName="Helvetica-BoldOblique", fontSize=9, textColor=ACCENT_TEAL, spaceBefore=4, spaceAfter=2) BODY = sty("BODY", fontName="Helvetica", fontSize=8.5, textColor=DARK_TEXT, leading=13, spaceAfter=3, alignment=TA_JUSTIFY) BULLET = sty("BULLET", fontName="Helvetica", fontSize=8.5, textColor=DARK_TEXT, leading=13, leftIndent=14, firstLineIndent=-8, spaceAfter=2) SMALL = sty("SMALL", fontName="Helvetica", fontSize=7.5, textColor=colors.HexColor("#555555"), leading=11, spaceAfter=2) MONO = sty("MONO", fontName="Courier", fontSize=7.5, textColor=DARK_TEXT, leading=11, backColor=GRAY_BG, leftIndent=8, spaceAfter=2) WARN = sty("WARN", fontName="Helvetica-Bold", fontSize=8.5, textColor=WARN_RED, spaceBefore=2, spaceAfter=2) KEY = sty("KEY", fontName="Helvetica-Bold", fontSize=8.5, textColor=DARK_BLUE, spaceBefore=2, spaceAfter=2) TABLE_HEAD_S = sty("TH", fontName="Helvetica-Bold", fontSize=8, textColor=colors.white, alignment=TA_CENTER) TABLE_CELL = sty("TC", fontName="Helvetica", fontSize=8, textColor=DARK_TEXT, leading=11, alignment=TA_LEFT) TABLE_CELLC = sty("TCC", fontName="Helvetica", fontSize=8, textColor=DARK_TEXT, leading=11, alignment=TA_CENTER) def bullet(txt, indent=14): return Paragraph(f"<bullet>\u2022</bullet> {txt}", BULLET) def bold(txt): return f"<b>{txt}</b>" def it(txt): return f"<i>{txt}</i>" def col(txt, c): return f'<font color="{c}">{txt}</font>' def hdr(p, text): """Section header with coloured background.""" d = Drawing(W - 3*cm, 20) d.add(Rect(0, 0, W - 3*cm, 18, fillColor=DARK_BLUE, strokeColor=None)) d.add(String(8, 5, text, fontName="Helvetica-Bold", fontSize=11, fillColor=colors.white)) p.append(d) p.append(Spacer(1, 4)) def subhdr(text): d = Drawing(W - 3*cm, 16) d.add(Rect(0, 0, W - 3*cm, 15, fillColor=MID_BLUE, strokeColor=None)) d.add(String(6, 4, text, fontName="Helvetica-Bold", fontSize=9.5, fillColor=colors.white)) return d def box(content_list, bg=BOX_BG, border=BOX_BORDER): """Wrap a list of flowables in a coloured box via Table.""" inner = [Spacer(1,4)] + content_list + [Spacer(1,4)] t = Table([[inner]], colWidths=[W - 3.2*cm]) t.setStyle(TableStyle([ ("BACKGROUND", (0,0), (-1,-1), bg), ("BOX", (0,0), (-1,-1), 1, border), ("LEFTPADDING", (0,0), (-1,-1), 8), ("RIGHTPADDING", (0,0), (-1,-1), 8), ("TOPPADDING", (0,0), (-1,-1), 2), ("BOTTOMPADDING", (0,0), (-1,-1), 4), ])) return t def std_table(headers, rows, col_widths=None): data = [[Paragraph(h, TABLE_HEAD_S) for h in headers]] for row in rows: data.append([Paragraph(str(c), TABLE_CELL) for c in row]) if not col_widths: n = len(headers) col_widths = [(W - 3.2*cm)/n] * n t = Table(data, colWidths=col_widths, repeatRows=1) style = [ ("BACKGROUND", (0,0), (-1,0), TABLE_HEAD), ("TEXTCOLOR", (0,0), (-1,0), colors.white), ("ROWBACKGROUNDS", (0,1), (-1,-1), [colors.white, TABLE_ALT]), ("GRID", (0,0), (-1,-1), 0.4, colors.HexColor("#BBBBBB")), ("LEFTPADDING", (0,0), (-1,-1), 5), ("RIGHTPADDING", (0,0), (-1,-1), 5), ("TOPPADDING", (0,0), (-1,-1), 3), ("BOTTOMPADDING", (0,0), (-1,-1), 3), ("VALIGN", (0,0), (-1,-1), "TOP"), ] t.setStyle(TableStyle(style)) return t def two_col(left_items, right_items): """Two-column layout.""" cw = (W - 3.4*cm) / 2 - 4 left_t = Table([[f] for f in left_items], colWidths=[cw]) right_t = Table([[f] for f in right_items], colWidths=[cw]) left_t.setStyle(TableStyle([("LEFTPADDING",(0,0),(-1,-1),0),("RIGHTPADDING",(0,0),(-1,-1),0),("TOPPADDING",(0,0),(-1,-1),0),("BOTTOMPADDING",(0,0),(-1,-1),0)])) right_t.setStyle(TableStyle([("LEFTPADDING",(0,0),(-1,-1),0),("RIGHTPADDING",(0,0),(-1,-1),0),("TOPPADDING",(0,0),(-1,-1),0),("BOTTOMPADDING",(0,0),(-1,-1),0)])) outer = Table([[left_t, right_t]], colWidths=[cw+4, cw+4]) outer.setStyle(TableStyle([ ("LEFTPADDING",(0,0),(-1,-1),0),("RIGHTPADDING",(0,0),(-1,-1),0), ("TOPPADDING",(0,0),(-1,-1),0),("BOTTOMPADDING",(0,0),(-1,-1),0), ("VALIGN",(0,0),(-1,-1),"TOP"), ])) return outer # ─── ASCII DIAGRAM HELPER ────────────────────────────────────────────────────── def ascii_box(lines, bg=GRAY_BG): content = [Paragraph(line, MONO) for line in lines] return box(content, bg=bg, border=colors.HexColor("#90A4AE")) # ══════════════════════════════════════════════════════════════════════════════ # BUILD DOCUMENT # ══════════════════════════════════════════════════════════════════════════════ out_path = "/tmp/workspace/pharmacology-cheatsheet/General_Pharmacology_Cheatsheet.pdf" doc = SimpleDocTemplate(out_path, pagesize=A4, leftMargin=1.5*cm, rightMargin=1.5*cm, topMargin=1.5*cm, bottomMargin=1.5*cm) story = [] # ───────────────────────────────────────────────────────────────────────────── # COVER HEADER # ───────────────────────────────────────────────────────────────────────────── cover_table = Table( [[Paragraph("GENERAL PHARMACOLOGY", TITLE)], [Paragraph("MBBS Professional Exam Cheat Sheet | All 16 Topics", SUBTITLE)]], colWidths=[W - 3*cm] ) cover_table.setStyle(TableStyle([ ("BACKGROUND", (0,0), (-1,-1), DARK_BLUE), ("TOPPADDING", (0,0), (-1,-1), 10), ("BOTTOMPADDING", (0,0), (-1,-1), 10), ("LEFTPADDING", (0,0), (-1,-1), 12), ])) story.append(cover_table) story.append(Spacer(1, 8)) # INDEX index_data = [ ["1. Routes of Administration", "2. Generic & Chemical Names", "3. Special Drug Delivery / TDDS"], ["4. Anaphylactic Shock", "5. Teratogenic Drugs", "6. Drug Antagonism"], ["7. Plasma Protein Binding", "8. First Pass Metabolism", "9. Bioavailability"], ["10. Omeprazole – Empty Stomach", "11. Zero & First Order Kinetics", "12. Plasma Half-Life"], ["13. Therapeutic Drug Monitoring", "14. Fixed Dose Combination", "15. Clinical Trials"], ["16. Adverse Drug Reactions", "", ""], ] idx_t = Table(index_data, colWidths=[(W-3*cm)/3]*3) idx_t.setStyle(TableStyle([ ("BACKGROUND", (0,0), (-1,-1), LIGHT_BLUE), ("TEXTCOLOR", (0,0), (-1,-1), DARK_BLUE), ("FONTNAME", (0,0), (-1,-1), "Helvetica"), ("FONTSIZE", (0,0), (-1,-1), 8), ("GRID", (0,0), (-1,-1), 0.3, MID_BLUE), ("LEFTPADDING", (0,0), (-1,-1), 6), ("TOPPADDING", (0,0), (-1,-1), 4), ("BOTTOMPADDING", (0,0), (-1,-1), 4), ])) story.append(idx_t) story.append(Spacer(1, 10)) # ════════════════════════════════════════════════════════════════════════ # TOPIC 1 – Routes of Administration # ════════════════════════════════════════════════════════════════════════ hdr(story, "1. ROUTES OF DRUG ADMINISTRATION") routes = [ ["Route", "Onset", "Bioavail.", "Advantages", "Disadvantages", "Examples"], ["IV", "Seconds", "100%", "Immediate, accurate titration, large vol.", "Irreversible, infection risk, skilled staff", "Morphine, Lignocaine"], ["IM", "10–30 min", "75–100%", "Faster than oral, depot possible", "Painful, nerve injury risk", "Penicillin, Vaccines"], ["SC", "15–30 min", "75–100%", "Sustained release, self-admin", "Small vol only (<2 mL), necrosis risk", "Insulin, Heparin"], ["Oral", "30–90 min", "Variable", "Safe, cheap, convenient", "First-pass, food interactions, slow", "Metformin, Aspirin"], ["Sublingual", "1–2 min", "High", "Bypasses first pass, rapid", "Small doses only, taste", "GTN, Buprenorphine"], ["Rectal", "5–30 min", "~50%", "Useful if vomiting/unconscious", "Irregular absorption, inconvenient", "Diazepam, Paracetamol"], ["Transdermal", "Hours", "Moderate", "Bypass first pass, sustained, non-invasive", "Slow onset, skin irritation", "GTN patch, Nicotine patch"], ["Inhalation", "Minutes", "High (local)", "Direct lung delivery, low systemic SE", "Difficult technique", "Salbutamol, Beclometasone"], ] story.append(std_table(routes[0], routes[1:], col_widths=[1.8*cm, 1.4*cm, 1.4*cm, 3.8*cm, 3.8*cm, 3.3*cm])) story.append(Spacer(1, 6)) # ════════════════════════════════════════════════════════════════════════ # TOPIC 2 – Generic & Chemical Names # ════════════════════════════════════════════════════════════════════════ hdr(story, "2. GENERIC AND CHEMICAL NAMES OF DRUGS") story.append(two_col( [ Paragraph(bold("Definitions"), H2), bullet("<b>Chemical name:</b> Full IUPAC structure name"), bullet("<b>Generic (INN) name:</b> Official non-proprietary name – used in prescriptions"), bullet("<b>Brand name:</b> Manufacturer's trade name (capital letter)"), Spacer(1,4), Paragraph(bold("Rule:") + " Prescriptions should always use <b>generic (INN)</b> names – reduces cost, prevents confusion", BODY), ], [ Paragraph(bold("Examples"), H2), std_table( ["Chemical Name", "Generic Name", "Brand"], [ ["2-Acetoxybenzoic acid", "Aspirin", "Ecosprin"], ["N-(4-hydroxyphenyl)acetamide", "Paracetamol", "Crocin"], ["7-Chloro-1,3-dihydro-1-methyl-5-phenyl-2H-1,4-benzodiazepin-2-one", "Diazepam", "Valium"], ["(S)-Omeprazole", "Esomeprazole", "Nexium"], ], col_widths=[5.5*cm, 2.5*cm, 1.8*cm] ), ] )) story.append(Spacer(1, 8)) # ════════════════════════════════════════════════════════════════════════ # TOPIC 3 – Special Drug Delivery / TDDS # ════════════════════════════════════════════════════════════════════════ hdr(story, "3. SPECIAL DRUG DELIVERY SYSTEMS | TRANSDERMAL (TDDS)") story.append(two_col( [ Paragraph(bold("Types of Special Delivery Systems"), H2), bullet("<b>SR/ER tablets:</b> Sustained release over 8–12 h (Nifedipine SR, Metformin XR)"), bullet("<b>Enteric-coated:</b> Resists gastric acid; dissolves at alkaline intestinal pH (Aspirin EC, Omeprazole)"), bullet("<b>OROS (osmotic pump):</b> Laser-drilled tablet, constant release (Nifedipine GITS)"), bullet("<b>Liposomes:</b> Phospholipid vesicles – targeted delivery (Liposomal Amphotericin B)"), bullet("<b>Nanoparticles:</b> <500 nm carriers – cancer targeting"), bullet("<b>Implants:</b> Long-term SC; Norplant (levonorgestrel 5 yr)"), Spacer(1,4), Paragraph(bold("TDDS Drug Requirements"), H2), bullet("High <b>lipid solubility</b>"), bullet("Low MW (<500 Da)"), bullet("Low effective dose (potent)"), bullet("Non-irritating to skin"), Spacer(1,4), Paragraph(bold("TDDS Examples"), H2), std_table(["Drug","Indication"],[ ["GTN","Angina"],["Scopolamine","Motion sickness"], ["Nicotine","Smoking cessation"],["Fentanyl","Chronic pain"], ["Clonidine","Hypertension"],["Estradiol","HRT"], ], col_widths=[4.5*cm, 4.0*cm]), ], [ Paragraph(bold("TDDS Patch Structure"), H2), ascii_box([ "┌─────────────────────────────────┐", "│ BACKING LAYER (occlusive film) │", "├─────────────────────────────────┤", "│ DRUG RESERVOIR (gel/matrix) │", "├─────────────────────────────────┤", "│ RATE-CONTROLLING MEMBRANE │", "├─────────────────────────────────┤", "│ CONTACT ADHESIVE LAYER │", "├─────────────────────────────────┤", "│ RELEASE LINER (peel before use) │", "└─────────────────────────────────┘", " ↓↓ Drug permeates skin ↓↓", " Stratum corneum → Dermis", " → Capillaries", ]), Spacer(1,6), Paragraph(bold("Advantages vs Disadvantages"), H2), std_table(["Advantage","Disadvantage"],[ ["Avoid first-pass metabolism","Slow onset of action"], ["Sustained drug levels","Skin irritation/allergy"], ["Non-invasive","Only lipophilic drugs qualify"], ["Easy removal (stops drug delivery)","Expensive"], ["Good patient compliance","Cannot use for high-dose drugs"], ], col_widths=[4.5*cm,4.5*cm]), ] )) story.append(PageBreak()) # ════════════════════════════════════════════════════════════════════════ # TOPIC 4 – Anaphylactic Shock # ════════════════════════════════════════════════════════════════════════ hdr(story, "4. MANAGEMENT OF ANAPHYLACTIC SHOCK") story.append(box([ Paragraph(bold("Definition:") + " Life-threatening Type I (IgE-mediated) hypersensitivity reaction with systemic mast cell/basophil degranulation.", BODY), Paragraph(bold("Features:") + " Urticaria, angioedema, bronchospasm, hypotension, tachycardia, loss of consciousness.", BODY), ], bg=WARN_YELLOW, border=WARN_BORDER)) story.append(Spacer(1,4)) story.append(two_col( [ Paragraph(bold("IMMEDIATE MANAGEMENT"), H2), bullet("1. <b>STOP</b> the offending agent"), bullet("2. Lay patient flat, legs elevated (Trendelenburg)"), bullet("3. <b>ADRENALINE (Epinephrine) 0.5 mg IM</b> (1:1000) into anterolateral thigh — <b>DRUG OF CHOICE</b>"), bullet(" Repeat every 5 min if no improvement"), bullet("4. <b>Oxygen</b> 10–15 L/min via face mask"), bullet("5. <b>IV access</b> + 0.9% NaCl rapid bolus (fluid resuscitation)"), bullet("6. <b>Chlorphenamine 10 mg IV</b> (H1 antihistamine — adjunct)"), bullet("7. <b>Hydrocortisone 200 mg IV</b> (prevents late-phase — adjunct)"), bullet("8. <b>Salbutamol nebulizer</b> if bronchospasm persists"), bullet("9. Refractory: IV adrenaline infusion; <b>Glucagon</b> if on β-blockers"), ], [ Paragraph(bold("Mechanism of Adrenaline"), H2), std_table(["Receptor","Effect","Benefit"],[ ["α1","Vasoconstriction","Reverses hypotension"], ["β1","↑ HR, ↑ contractility","Treats shock"], ["β2","Bronchodilation","Relieves bronchospasm"], ["β2","↓ Mast cell degranulation","Limits mediator release"], ], col_widths=[1.8*cm,3.8*cm,3.8*cm]), Spacer(1,6), Paragraph(bold("Key Points"), H2), bullet("Adrenaline is the ONLY life-saving drug"), bullet("Antihistamines and steroids are ADJUNCTS only"), bullet("IM route preferred over IV in non-arrested patients"), bullet("Adrenaline dose in children: 0.01 mg/kg IM (max 0.5 mg)"), Spacer(1,4), box([Paragraph(bold("MNEMONIC: STOAE") + " — Stop, Trendelenburg, Oxygen, Adrenaline, Extras (fluids/steroids/antihistamine)", BODY)], bg=ACCENT_GREEN, border=ACCENT_TEAL), ] )) story.append(Spacer(1, 8)) # ════════════════════════════════════════════════════════════════════════ # TOPIC 5 – Teratogenic Drugs # ════════════════════════════════════════════════════════════════════════ hdr(story, "5. TERATOGENIC DRUGS") story.append(two_col( [ Paragraph(bold("Definition:") + " Agent causing structural/functional defect in embryo/fetus", BODY), Paragraph(bold("Most vulnerable period:") + " <b>Organogenesis (Wk 3–8)</b> — differentiation of organs", BODY), Spacer(1,4), Paragraph(bold("FDA Pregnancy Categories"), H2), std_table(["Category","Safety","Example"],[ ["A","Safe in humans","Folic acid, Thyroxine"], ["B","Safe in animals; no human data","Metformin, Amoxicillin"], ["C","Animal risk; inadequate human data","Aspirin (low dose), Furosemide"], ["D","Human fetal risk; benefit > risk","Phenytoin, Valproate, Carbamazepine"], ["X","CONTRAINDICATED in pregnancy","Thalidomide, Isotretinoin, Warfarin, MTX"], ], col_widths=[1.5*cm, 4.5*cm, 3.5*cm]), ], [ Paragraph(bold("Key Teratogenic Drugs"), H2), std_table(["Drug","Effect"],[ ["Thalidomide","Phocomelia (limb reduction)"], ["Valproic acid","Neural tube defects (spina bifida)"], ["Phenytoin","Fetal hydantoin syndrome"], ["Warfarin (T1)","Warfarin embryopathy, nasal hypoplasia"], ["Tetracyclines","Yellow teeth, bone growth inhibition"], ["Isotretinoin (Vit A)","CNS, cardiac, craniofacial defects"], ["ACE inhibitors (T2/T3)","Renal tubular dysplasia, oligohydramnios"], ["Methotrexate","Neural tube defects, limb anomalies"], ["Diethylstilbestrol","Vaginal clear cell carcinoma (daughters)"], ["Lithium","Ebstein's cardiac anomaly"], ["Aminoglycosides","Ototoxicity (CN VIII damage)"], ["Carbamazepine","Neural tube defects"], ["Misoprostol","Möbius syndrome"], ], col_widths=[4.0*cm, 5.5*cm]), ] )) story.append(PageBreak()) # ════════════════════════════════════════════════════════════════════════ # TOPIC 6 – Drug Antagonism # ════════════════════════════════════════════════════════════════════════ hdr(story, "6. DRUG ANTAGONISM") story.append(two_col( [ Paragraph(bold("Types of Antagonism"), H2), std_table(["Type","Mechanism","Key Feature","Example"],[ ["Competitive (reversible)","Competes at same receptor","Parallel right shift; Emax UNCHANGED","Naloxone vs Morphine; Atropine vs ACh"], ["Non-competitive (irreversible)","Binds same/allosteric site permanently","Emax REDUCED; right shift","Phenoxybenzamine vs Adrenaline"], ["Partial agonist","Lower intrinsic activity at receptor","Competes with full agonist","Buprenorphine vs Morphine"], ["Physiological","Opposite effects via different receptors","Different receptors, same endpoint","Adrenaline vs Histamine (bronchi)"], ["Chemical","Direct chemical neutralization","No receptor involved","Protamine vs Heparin; EDTA chelation"], ["Pharmacokinetic","Alters PK of other drug","Changes absorption/metabolism","Rifampicin (inducer) vs OCP"], ], col_widths=[2.2*cm, 3.2*cm, 2.8*cm, 3.0*cm]), ], [ Paragraph(bold("Dose-Response Curve Diagram"), H2), ascii_box([ "Effect", " |", " |───────────────────────────── Agonist alone (Emax)", " | /", " | / ───────────── Competitive antagonist", " | / (parallel right shift; same Emax)", " | /", " | / ─ ─ ─ ─ ─ ─ Non-competitive antagonist", " | / (right shift + REDUCED Emax)", " | /", " └─────────────────────────────▶ Log [Dose]", ]), Spacer(1,4), box([ Paragraph(bold("Exam Key Points:"), H2), bullet("Competitive: Right shift, SAME Emax, overcome by ↑dose"), bullet("Non-competitive: Reduced Emax, CANNOT be overcome"), bullet("Chemical antagonism has NO receptor involvement"), ], bg=ACCENT_GREEN, border=ACCENT_TEAL), ] )) story.append(Spacer(1, 8)) # ════════════════════════════════════════════════════════════════════════ # TOPIC 7 – Plasma Protein Binding # ════════════════════════════════════════════════════════════════════════ hdr(story, "7. PLASMA PROTEIN BINDING") story.append(two_col( [ Paragraph(bold("Key Concept"), H2), Paragraph("Drugs circulate as <b>bound</b> (inactive reservoir) + <b>free/unbound</b> (pharmacologically ACTIVE) fractions.", BODY), Spacer(1,4), std_table(["Protein","Binds","Examples"],[ ["Albumin","Acidic drugs","Warfarin (99%), Phenytoin (90%), Furosemide (99%), Aspirin"], ["α1-acid glycoprotein","Basic drugs","Lignocaine, Propranolol, Quinidine"], ["Globulins","Hormones, vitamins","Cortisol, Vit D, Testosterone"], ], col_widths=[3.0*cm, 3.0*cm, 3.5*cm]), Spacer(1,4), Paragraph(bold("Only FREE drug:"), H2), bullet("Crosses blood-brain barrier"), bullet("Filtered at glomerulus (renally eliminated)"), bullet("Metabolized by liver"), bullet("Exerts pharmacological effect"), bullet("Determines volume of distribution"), ], [ Paragraph(bold("Clinical Significance"), H2), std_table(["Situation","Effect"],[ ["Hypoalbuminaemia (liver disease, nephrotic syndrome)","↑ Free drug → toxicity at normal doses"], ["Drug displacement from binding sites","Transient ↑ free drug (rapidly re-equilibrates)"], ["Neonates (low albumin)","↑ Free drug fraction — adjust dose"], ["Renal failure","Uremic acids displace acidic drugs"], ], col_widths=[4.5*cm, 4.9*cm]), Spacer(1,6), box([ Paragraph(bold("Important Note (Katzung):"), WARN), Paragraph("Protein binding displacement alone rarely causes clinically significant interactions because displaced drug is quickly redistributed and eliminated. Relevant only if the displacing drug <b>also inhibits clearance</b>.", BODY), ], bg=WARN_YELLOW, border=WARN_BORDER), ] )) story.append(PageBreak()) # ════════════════════════════════════════════════════════════════════════ # TOPIC 8 – First Pass Metabolism # ════════════════════════════════════════════════════════════════════════ hdr(story, "8. FIRST PASS METABOLISM") story.append(two_col( [ Paragraph(bold("Definition:") + " Metabolism of drug in <b>gut wall + liver</b> before reaching systemic circulation after oral administration", BODY), Spacer(1,4), ascii_box([ "ORAL DRUG", " ↓", "GI Lumen", " ↓ (CYP3A4 in gut wall)", "Portal Vein", " ↓", "LIVER (CYP450 enzymes)", " ↓", "SYSTEMIC CIRCULATION", "(reduced amount — ↓ bioavailability)", ]), Spacer(1,4), Paragraph(bold("Drugs with High First Pass Effect"), H2), std_table(["Drug","Oral Bioavailability"],[ ["GTN (Glyceryl trinitrate)","< 1%"], ["Lidocaine","~ 3%"], ["Propranolol","~ 25%"], ["Morphine","~ 25%"], ["Testosterone","Very low"], ["Aspirin","~70% (partly)"], ], col_widths=[5.5*cm, 4.0*cm]), ], [ Paragraph(bold("Ways to Bypass First Pass"), H2), std_table(["Route","Example"],[ ["Sublingual","GTN tablet"], ["Transdermal","GTN patch, Estradiol patch"], ["Rectal (50% bypass)","Diazepam, Paracetamol suppository"], ["IV / IM / SC","Morphine injection"], ["Inhalation","Salbutamol MDI"], ], col_widths=[4.5*cm, 5.0*cm]), Spacer(1,6), Paragraph(bold("Factors Affecting First Pass"), H2), bullet("<b>Hepatic blood flow</b> — reduced in liver disease → ↑ bioavailability"), bullet("<b>Enzyme induction</b> (Rifampicin, Phenobarbitone) → ↓ bioavailability"), bullet("<b>Enzyme inhibition</b> (Cimetidine, Grapefruit) → ↑ bioavailability"), bullet("<b>CYP3A4</b> in gut wall — major site for pre-systemic metabolism"), bullet("<b>Cardiac output</b> — high extraction drugs are flow-dependent"), ] )) story.append(Spacer(1, 8)) # ════════════════════════════════════════════════════════════════════════ # TOPIC 9 – Bioavailability # ════════════════════════════════════════════════════════════════════════ hdr(story, "9. BIOAVAILABILITY") story.append(two_col( [ Paragraph(bold("Definition:") + " Fraction of administered dose reaching systemic circulation in pharmacologically active form", BODY), Spacer(1,4), ascii_box([ "F = (AUC_oral / AUC_IV) × 100%", "", "AUC = Area Under Plasma Conc.–Time Curve", ]), Spacer(1,4), ascii_box([ "PLASMA CONC–TIME CURVE", "Cp | ╭─────────╮", " | / \\ ← IV (100%)", " | / ╭────╮", " | / / \\ ← Oral (<100%)", " | / / \\", " └───────────────────▶ Time", " ↑ Tmax", ]), Spacer(1,4), Paragraph(bold("Absolute vs Relative Bioavailability"), H2), bullet("<b>Absolute:</b> Compared to IV (reference = 100%)"), bullet("<b>Relative:</b> Compared to another oral formulation"), ], [ Paragraph(bold("Bioavailability by Route"), H2), std_table(["Route","F (approx.)"],[ ["IV","100%"], ["IM","75–100%"], ["SC","75–100%"], ["Sublingual","50–75%"], ["Rectal","~50%"], ["Oral","5–100% (variable)"], ["Transdermal","Variable"], ], col_widths=[5*cm, 4.5*cm]), Spacer(1,6), Paragraph(bold("Factors Affecting Bioavailability"), H2), bullet("First pass metabolism (main factor for oral drugs)"), bullet("Drug solubility and dissolution rate"), bullet("Gut motility (↑ motility → ↓ absorption time)"), bullet("Food effect (can increase or decrease)"), bullet("Drug formulation (particle size, excipients)"), bullet("Drug–drug interactions (e.g., antacids + fluoroquinolones)"), bullet("Hepatic/gut wall CYP enzyme activity"), ] )) story.append(PageBreak()) # ════════════════════════════════════════════════════════════════════════ # TOPIC 10 – Omeprazole Empty Stomach # ════════════════════════════════════════════════════════════════════════ hdr(story, "10. WHY IS OMEPRAZOLE GIVEN ON EMPTY STOMACH IN THE MORNING?") story.append(two_col( [ Paragraph(bold("Mechanism of Omeprazole (PPI)"), H2), bullet("Prodrug — activated in <b>acidic canalicular pH</b> of parietal cells"), bullet("Active sulphenamide form <b>irreversibly inhibits H⁺/K⁺ ATPase</b> (proton pump)"), bullet("Proton pump must be <b>ACTIVE (secreting acid)</b> to be inhibited"), bullet("Given as <b>enteric-coated</b> capsule (unstable in gastric acid)"), Spacer(1,6), Paragraph(bold("Why Empty Stomach?"), H2), bullet("After overnight fast → maximum proton pumps recruited to canalicular membrane → ready to be inhibited"), bullet("Food intake after dosing stimulates acid secretion → activates pumps → omeprazole now present to bind them"), bullet("Timing: <b>30–60 minutes BEFORE breakfast</b> = optimal"), Spacer(1,4), box([Paragraph(bold("Note:") + " Evening dosing is LESS effective. Twice-daily dosing for nocturnal GERD.", BODY)], bg=ORANGE_BG, border=ORANGE_BDR), ], [ Paragraph(bold("Sequence for Maximum Effect"), H2), ascii_box([ "OVERNIGHT FAST", " ↓", "Proton pumps recruited to", "canalicular membrane (most active)", " ↓", "Take Omeprazole 30–60 min BEFORE", "breakfast (enteric coat dissolves", "in small intestine)", " ↓", "Absorbed → portal blood →", "parietal cell → converted to", "active SULPHENAMIDE", " ↓", "Eat breakfast → stimulates", "acid secretion → pumps ACTIVATE", " ↓", "Sulphenamide irreversibly binds", "active H⁺/K⁺ ATPase", " ↓", "MAXIMUM ACID SUPPRESSION", ]), ] )) story.append(Spacer(1, 8)) # ════════════════════════════════════════════════════════════════════════ # TOPIC 11 – Zero and First Order Kinetics # ════════════════════════════════════════════════════════════════════════ hdr(story, "11. ZERO ORDER AND FIRST ORDER KINETICS") story.append(two_col( [ Paragraph(bold("First Order Kinetics"), H2), std_table(["Feature","Detail"],[ ["Definition","Constant FRACTION (%) eliminated per unit time"], ["Graph (linear)","Exponential decline"], ["Graph (semi-log)","STRAIGHT LINE"], ["Half-life","CONSTANT"], ["When?","Most drugs at therapeutic doses"], ["Formula","dC/dt = –k × C"], ], col_widths=[3.5*cm, 6.0*cm]), Spacer(1,4), Paragraph(bold("Zero Order Kinetics"), H2), std_table(["Feature","Detail"],[ ["Definition","Constant AMOUNT eliminated per unit time"], ["Graph (linear)","STRAIGHT LINE (linear decline)"], ["Graph (semi-log)","Curved line"], ["Half-life","NOT constant (increases with dose)"], ["When?","Elimination SATURATED (capacity-limited)"], ["Danger","Small ↑ in dose → huge ↑ in plasma level"], ["Examples","Phenytoin, Ethanol, Aspirin (high dose)"], ], col_widths=[3.5*cm, 6.0*cm]), ], [ Paragraph(bold("Graphical Comparison"), H2), ascii_box([ "FIRST ORDER (semi-log plot):", "log Cp | ─────────────────────────", " │ ──────", " │ ──────", " └──────────────────────▶ Time", " (Straight line)", "", "ZERO ORDER (linear plot):", "Cp | ─────────────────────", " │ ─────", " └──────────────────────────▶ Time", " (Straight line on linear)", ]), Spacer(1,6), Paragraph(bold("Michaelis-Menten Equation"), H2), ascii_box([ "v = Vmax × C", " ─────────────", " Km + C", "", "When C << Km → FIRST ORDER", "When C >> Km → ZERO ORDER", ]), Spacer(1,4), box([ Paragraph(bold("Classic Exam Example – PHENYTOIN:"), WARN), Paragraph("Switches from first-order to zero-order at therapeutic doses. Small dose changes cause DISPROPORTIONATE plasma level changes → toxicity.", BODY), ], bg=WARN_YELLOW, border=WARN_BORDER), ] )) story.append(PageBreak()) # ════════════════════════════════════════════════════════════════════════ # TOPIC 12 – Plasma Half Life # ════════════════════════════════════════════════════════════════════════ hdr(story, "12. PLASMA HALF LIFE (t½)") story.append(two_col( [ Paragraph(bold("Definition:") + " Time for plasma concentration to fall to <b>50% of its initial value</b>", BODY), Spacer(1,4), ascii_box([ "t½ = 0.693 × Vd / CL", "", "Vd = Volume of distribution (L)", "CL = Clearance (L/h)", "0.693 = ln2", ]), Spacer(1,4), ascii_box([ "% REMAINING (half-life concept):", "After 1 t½ → 50% remains", "After 2 t½ → 25% remains", "After 3 t½ → 12.5% remains", "After 4 t½ → 6.25% remains", "After 5 t½ → ~3% remains (97% eliminated)", ]), Spacer(1,4), ascii_box([ "ACCUMULATION TO STEADY STATE:", "% SS | ─────────────── 100% (5 t½)", " | ─────── 94% (4 t½)", " | ─── 75% (3 t½)", " | 50% (2 t½)", " └─────────────────────▶ t½", ]), ], [ Paragraph(bold("Clinical Significance"), H2), std_table(["Parameter","Relationship to t½"],[ ["Steady state", "Reached after ~4–5 t½"], ["Drug elimination", "~97% eliminated after 5 t½"], ["Dosing interval", "Usually = one t½"], ["Loading dose needed", "If t½ is long (to reach SS quickly)"], ], col_widths=[3.5*cm, 5.5*cm]), Spacer(1,4), Paragraph(bold("Clinical Examples"), H2), std_table(["Drug","t½","Clinical Note"],[ ["Penicillin G","30 min","4–6 hourly dosing needed"], ["Digoxin","36 hours","Once daily; ~7 days to SS"], ["Warfarin","36–42 hours","INR 3–4 days to stabilize"], ["Phenobarbitone","4–5 days","Once daily"], ["Amiodarone","40–55 days","Very long; drug interactions linger"], ["Thiopentone","Short dist. t½","Short action; cumulation on repeat"], ], col_widths=[3.0*cm, 2.2*cm, 4.3*cm]), Spacer(1,4), box([Paragraph(bold("Vd ↑") + " → t½ ↑ (drug distributes widely, less available for elimination). " + bold("CL ↑") + " → t½ ↓ (eliminated faster).", BODY)], bg=BOX_BG, border=BOX_BORDER), ] )) story.append(Spacer(1, 8)) # ════════════════════════════════════════════════════════════════════════ # TOPIC 13 – Therapeutic Drug Monitoring # ════════════════════════════════════════════════════════════════════════ hdr(story, "13. THERAPEUTIC DRUG MONITORING (TDM)") story.append(two_col( [ Paragraph(bold("Definition:") + " Measurement of drug levels in plasma to maintain concentrations within the <b>Therapeutic Window</b>", BODY), Spacer(1,4), ascii_box([ "THERAPEUTIC WINDOW", "Cp |───────────────────── MTC (Minimum Toxic Conc.)", " | THERAPEUTIC RANGE", " |───────────────────── MEC (Min. Effective Conc.)", " | SUBTHERAPEUTIC", " └──────────────────────▶ Time", " Goal: Keep drug level BETWEEN MEC and MTC", ]), Spacer(1,4), Paragraph(bold("Indications for TDM"), H2), bullet("<b>Narrow Therapeutic Index (NTI)</b> drugs"), bullet("Non-linear pharmacokinetics (Phenytoin)"), bullet("High inter-individual variability"), bullet("Serious/irreversible toxicity risk (aminoglycosides)"), bullet("Suspected non-compliance"), bullet("Suspected toxicity"), bullet("Organ failure (renal/hepatic impairment)"), ], [ Paragraph(bold("Drugs Monitored (+ Therapeutic Ranges)"), H2), std_table(["Drug","Therapeutic Range","Main Concern"],[ ["Digoxin","0.8–2 ng/mL","Narrow TI; toxicity common"], ["Phenytoin","10–20 μg/mL","Zero-order kinetics, toxicity"], ["Lithium","0.6–1.2 mEq/L","Narrow TI; serious neurotoxicity"], ["Aminoglycosides","Peak 5–10; Trough <2 μg/mL","Nephro/ototoxicity"], ["Vancomycin","Trough 10–20 μg/mL","Nephrotoxicity"], ["Carbamazepine","4–12 μg/mL","NTI"], ["Valproate","50–100 μg/mL","NTI"], ["Theophylline","10–20 μg/mL","Narrow TI, cardiac arrhythmias"], ["Cyclosporin","100–400 ng/mL","Nephrotoxicity, rejection"], ["Methotrexate","<1 μmol/L @ 48h","High-dose toxicity"], ], col_widths=[2.8*cm, 2.8*cm, 3.9*cm]), Spacer(1,4), box([Paragraph(bold("Sampling:") + " At steady state (after 4–5 t½). Trough level (just before next dose) for most drugs. Peak and trough for aminoglycosides.", BODY)], bg=ACCENT_GREEN, border=ACCENT_TEAL), ] )) story.append(PageBreak()) # ════════════════════════════════════════════════════════════════════════ # TOPIC 14 – Fixed Dose Combination # ════════════════════════════════════════════════════════════════════════ hdr(story, "14. FIXED DOSE COMBINATION (FDC)") story.append(two_col( [ Paragraph(bold("Definition:") + " Two or more APIs combined in a <b>fixed ratio</b> in a single dosage form", BODY), Spacer(1,4), Paragraph(bold("Advantages"), H2), bullet("Synergistic effect → enhanced efficacy at lower individual doses"), bullet("Reduced adverse effects (lower doses used)"), bullet("Improved patient compliance (fewer tablets)"), bullet("Delays development of drug resistance (anti-TB, HIV)"), bullet("Convenient and cost-effective"), Spacer(1,4), Paragraph(bold("Disadvantages"), H2), bullet("Cannot adjust dose of individual component"), bullet("Cannot identify which drug caused ADR"), bullet("Pharmacokinetic incompatibility possible"), bullet("Regulatory challenges"), ], [ Paragraph(bold("Important FDC Examples"), H2), std_table(["FDC Name","Components","Use"],[ ["Augmentin","Amoxicillin + Clavulanate","Beta-lactamase producing organisms"], ["Co-trimoxazole","Trimethoprim + Sulfamethoxazole","UTI, PCP prophylaxis"], ["Sinemet","Levodopa + Carbidopa","Parkinson's disease"], ["Kaletra","Lopinavir + Ritonavir","HIV (ritonavir boosts lopinavir levels)"], ["Combivir","Zidovudine + Lamivudine","HIV"], ["Atripla","TDF + FTC + Efavirenz","HIV (once daily)"], ["Anti-TB (RHEZ)","Rifampicin + INH + Ethambutol + PZA","Tuberculosis"], ["Lodoz","Bisoprolol + HCTZ","Hypertension"], ["Glucovance","Metformin + Glibenclamide","Type 2 Diabetes"], ], col_widths=[2.4*cm, 4.0*cm, 3.1*cm]), ] )) story.append(Spacer(1, 8)) # ════════════════════════════════════════════════════════════════════════ # TOPIC 15 – Clinical Trials # ════════════════════════════════════════════════════════════════════════ hdr(story, "15. CLINICAL TRIALS") story.append(two_col( [ Paragraph(bold("Definition:") + " Prospective study in human participants evaluating a new drug/device intervention", BODY), Spacer(1,4), Paragraph(bold("Phases of Clinical Trials"), H2), std_table(["Phase","Subjects","Focus","Design"],[ ["0 (Microdosing)","<10 healthy volunteers","Sub-therapeutic PK; target binding","Observational"], ["I","20–100 healthy volunteers","SAFETY, tolerance, PK, dose range","Open label"], ["II","100–300 patients","EFFICACY + safety; dose optimization","Double-blind, placebo-controlled"], ["III (Pivotal)","300–3000+ patients","Confirm efficacy vs standard treatment","Multicenter RCT"], ["IV (Post-marketing)","General population","Rare ADRs; long-term safety","Pharmacovigilance"], ], col_widths=[1.8*cm, 3.0*cm, 3.2*cm, 3.0*cm]), Spacer(1,4), box([Paragraph(bold("Phase III is basis for regulatory approval") + " (FDA/CDSCO). Phase IV is where rare/delayed ADRs emerge — drug may be WITHDRAWN (e.g., Rofecoxib/Vioxx).", BODY)], bg=WARN_YELLOW, border=WARN_BORDER), ], [ Paragraph(bold("Key Study Design Terms"), H2), std_table(["Term","Definition"],[ ["Randomization","Random assignment to groups — eliminates selection bias"], ["Single-blind","Patient unaware of treatment allocation"], ["Double-blind","Both patient AND investigator unaware"], ["Triple-blind","Patient + investigator + statistician unaware"], ["Placebo","Inert substance identical in appearance to test drug"], ["Crossover design","Each patient receives both treatments sequentially"], ["Informed consent","Mandatory ethical requirement before enrolment"], ["ITT analysis","Intention-to-treat — all randomized patients analyzed"], ], col_widths=[3.5*cm, 5.5*cm]), Spacer(1,4), Paragraph(bold("Ethical Requirements (Declaration of Helsinki)"), H2), bullet("Informed written consent from all participants"), bullet("Independent Ethics Committee (IEC) approval"), bullet("Right to withdraw at any time without penalty"), bullet("Scientific integrity + pre-registration of trial"), ] )) story.append(PageBreak()) # ════════════════════════════════════════════════════════════════════════ # TOPIC 16 – Adverse Drug Reactions # ════════════════════════════════════════════════════════════════════════ hdr(story, "16. ADVERSE DRUG REACTIONS (ADR)") story.append(Paragraph(bold("WHO Definition:") + " Any noxious, unintended, and undesired effect of a drug occurring at doses used for prophylaxis, diagnosis, or therapy", BODY)) story.append(Spacer(1,4)) story.append(two_col( [ Paragraph(bold("Rawlins & Thompson Classification"), H2), std_table(["Type","Name","Features","Examples"],[ ["A","Augmented","Predictable; dose-dependent; ~80% of ADRs; extension of pharmacology","Bleeding (Warfarin), Hypoglycemia (Insulin), Bradycardia (Propranolol)"], ["B","Bizarre","Unpredictable; dose-independent; immunological or idiosyncratic","Anaphylaxis (Penicillin), Aplastic anemia (Chloramphenicol), Malignant hyperthermia (Succinylcholine)"], ["C","Chronic","Occur with prolonged use","Adrenal suppression (long-term steroids), Tardive dyskinesia (antipsychotics)"], ["D","Delayed","Appear long after drug exposure","Carcinogenesis (DES), Teratogenicity"], ["E","End of use","Withdrawal reactions on stopping drug","Opioid withdrawal, Rebound hypertension (Clonidine)"], ["F","Failure","Unexpected failure of therapy","Drug resistance, Subtherapeutic levels"], ], col_widths=[0.8*cm, 2.0*cm, 3.5*cm, 3.2*cm]), ], [ Paragraph(bold("ADR Severity Grading"), H2), std_table(["Grade","Features","Examples"],[ ["Mild","No therapy needed, not disabling","Mild nausea, dizziness"], ["Moderate","Requires change in therapy","Rash, vomiting"], ["Severe","Life-threatening, hospitalization required","SJS, Anaphylaxis, Agranulocytosis"], ], col_widths=[1.6*cm, 3.5*cm, 4.4*cm]), Spacer(1,6), Paragraph(bold("Important ADR Examples"), H2), std_table(["Drug","ADR"],[ ["ACE inhibitors","Dry cough (↑ bradykinin)"], ["Aminoglycosides","Nephrotoxicity, Ototoxicity"], ["Chloramphenicol","Aplastic anemia, Grey baby syndrome"], ["Metformin","Lactic acidosis"], ["Statins","Myopathy, Rhabdomyolysis"], ["Quinolones","Tendon rupture, QT prolongation"], ["Clozapine","Agranulocytosis"], ["Halothane","Hepatitis"], ["Sulfonamides","Stevens-Johnson syndrome"], ], col_widths=[3.5*cm, 6.0*cm]), ] )) story.append(Spacer(1,4)) story.append(two_col( [ Paragraph(bold("Pharmacovigilance"), H2), bullet("Science of monitoring drug safety post-marketing"), bullet("<b>Yellow Card</b> (UK), <b>MedWatch</b> (USA), <b>PVPI</b> (India)"), bullet("<b>Naranjo Algorithm</b>: assesses causality — Definite / Probable / Possible / Doubtful"), ], [ Paragraph(bold("Factors Predisposing to ADRs"), H2), bullet("Age extremes (neonates, elderly — altered PK/PD)"), bullet("Renal/hepatic impairment"), bullet("Polypharmacy (drug interactions)"), bullet("Genetic polymorphisms (G6PD deficiency, slow/fast acetylators)"), bullet("Previous history of drug allergy"), ] )) # ── FOOTER ──────────────────────────────────────────────────────────────────── story.append(Spacer(1, 12)) story.append(HRFlowable(width="100%", thickness=1, color=DARK_BLUE)) story.append(Spacer(1, 4)) story.append(Paragraph( "<i>References: Katzung's Basic & Clinical Pharmacology 16e | Goodman & Gilman's Pharmacological Basis of Therapeutics | KD Tripathi's Essentials of Medical Pharmacology</i>", SMALL )) # ─── BUILD PDF ──────────────────────────────────────────────────────────────── doc.build(story) print(f"PDF generated: {out_path}") PYEOF echo "Script written"
cd /tmp/workspace/pharmacology-cheatsheet && python gen_pdf.py 2>&1
ls -lh /tmp/workspace/pharmacology-cheatsheet/General_Pharmacology_Cheatsheet.pdf
General Pharmacology Cheatsheet
PDF Document · PDF
- Color-coded section headers for all 16 topics
- Structured tables for routes of administration, teratogenic drugs, TDM ranges, FDC examples, clinical trial phases, ADR classification, and more
- ASCII diagrams for:
- Dose-response curves (competitive vs non-competitive antagonism)
- Plasma concentration-time curves (bioavailability)
- TDDS transdermal patch structure
- First order vs zero order kinetics graphs
- Omeprazole mechanism flowchart
- Half-life and steady-state accumulation diagrams
- Therapeutic window diagram
- Highlighted boxes for exam-critical points, warnings (Phenytoin, protein binding caveat), and mnemonics
- Two-column layout throughout to maximize information density
- References to Katzung, Goodman & Gilman, and KD Tripathi at the footer
Now answer the ANS part
Autonomic Nervous System - MBBS Professional Exam Answers
SECTION 1: CHOLINERGIC / PARASYMPATHETIC SYSTEM
ANS-C1: Organophosphorus (OP) Poisoning
Mechanism:
OP COMPOUND
↓
Irreversibly binds AChE active site
↓
ACh accumulates at:
┌──────────────────────────────────────────────┐
│ Muscarinic receptors │ Nicotinic receptors│
│ (PNS postganglionic) │ (NMJ + ganglia) │
│ │ │
│ MUSCARINIC SIGNS │ NICOTINIC SIGNS │
│ (DUMBELS / SLUDGE) │ (MTWHF) │
└──────────────────────────────────────────────┘
Clinical Features:
- S - Salivation, Sweating
- L - Lacrimation
- U - Urination (involuntary)
- D - Defecation/Diarrhea
- G - GI cramps, vomiting
- E - Emesis + B - Bronchospasm, Bradycardia, L - Lacrimation, S - Secretions
- M - Muscle weakness/fasciculations
- T - Tachycardia (ganglionic stimulation)
- W - Weakness
- H - Hypertension (early)
- F - Fasciculations → paralysis (respiratory failure = main cause of death)
Diagnosis:
- Plasma / RBC cholinesterase levels - reduced (RBC AChE more specific)
- Miosis (pinpoint pupils) - hallmark
Management:
- Remove patient from exposure, remove clothing
- Wash skin with soap and water
- 1.2-3 mg IV bolus initially (depending on severity)
- Double dose every 5 minutes until atropinization achieved:
- Chest clear on auscultation (no wheeze)
- Heart rate >80/min
- Systolic BP >80 mmHg
- Dry secretions
- Note: Miosis/tachycardia are NOT endpoints for atropinization
- Atropine does NOT reverse muscle weakness (nicotinic effect)
- Very large doses (100s of mg) may be needed in severe poisoning
- Mechanism: Displaces OP from AChE active site, reactivating the enzyme
- Reverses BOTH muscarinic AND nicotinic (muscle paralysis) symptoms
- Must be given EARLY - before "aging" (irreversible covalent bond formation between OP and AChE - occurs within 24-48 hours)
- Dose: 30 mg/kg IV bolus, then 8 mg/kg/hour infusion (WHO recommendation)
- Continue for 24-48 hours monitoring AChE levels
- NOT useful for carbamates (reversible AChE inhibitors)
- Airway protection + mechanical ventilation (respiratory failure is cause of death)
- Benzodiazepines for seizures
- AVOID: Succinylcholine (prolonged paralysis), ester local anesthetics, β-blockers
OP POISONING TREATMENT SUMMARY
─────────────────────────────────────────────
DECONTAMINATION
↓
ATROPINE IV (for muscarinic signs)
Endpoint: Dry chest, HR>80, BP>80
↓
PRALIDOXIME IV (if early - before aging)
Reverses muscle weakness too
↓
AIRWAY + VENTILATION
(respiratory paralysis = #1 killer)
↓
BENZODIAZEPINES for seizures
─────────────────────────────────────────────
ANS-C2: Myasthenia Gravis (MG)
Definition:
Pathophysiology:
NORMAL NMJ:
Motor nerve → ACh release → Nicotinic receptor (N2) → Muscle contraction
MYASTHENIA GRAVIS:
IgG antibodies → Attack ACh receptors (N2 type) on postsynaptic membrane
↓
↓ Number of functional ACh receptors (~70% reduction)
↓
Impaired muscle contraction → Weakness
(Fatigable - worsens with use, improves with rest)
Features:
- Ocular (most common first symptom): Ptosis, diplopia
- Bulbar: Dysarthria, dysphagia, facial weakness, nasal voice
- Limb weakness: Proximal > distal, fluctuating
- Respiratory: Myasthenic crisis (respiratory failure - emergency)
- Thymic abnormality: 75% have thymic changes; 10-15% thymoma
- Worse: Exercise, heat, infections, medications
- Better: Rest, cold
Investigations:
- Tensilon (Edrophonium) test: Short-acting AChE inhibitor IV → dramatic but brief improvement in ptosis → confirms MG
- Anti-AChR antibodies (positive in 85-90%)
- Anti-MuSK antibodies (seronegative MG)
- EMG: Decremental response on repetitive nerve stimulation
- CT chest: Thymoma
Drug Treatment:
| Drug | Type | Dose/Route | Notes |
|---|---|---|---|
| Pyridostigmine | Reversible AChE inhibitor | 60 mg oral, 4-6 hourly | First-line symptomatic treatment |
| Neostigmine | Reversible AChE inhibitor | SC/IV | For acute/parenteral use |
| Prednisolone | Corticosteroid | High dose oral | Immunosuppression |
| Azathioprine | Immunosuppressant | Oral | Steroid-sparing |
| Mycophenolate | Immunosuppressant | Oral | Alternative |
| IV Immunoglobulin | Immunomodulation | IV infusion | Myasthenic crisis |
| Plasma exchange | Removes antibodies | Myasthenic crisis | |
| Thymectomy | Surgery | Thymoma; beneficial in AChR+ MG |
- ICU, intubation
- IV Ig or plasmapheresis
- Temporarily stop pyridostigmine
- Aminoglycosides, Fluoroquinolones (worsen NMJ transmission)
- Beta-blockers, Calcium channel blockers
- Chloroquine, Penicillamine
- Neuromuscular blockers (exaggerated response)
ANS-C3: Classification of Anticholinesterases (AChE Inhibitors)
Mechanism:
ACh + AChE → Choline + Acetic acid (normal)
AChE Inhibitor → Blocks AChE → ACh persists → ↑ Cholinergic effects
Classification:
| Subgroup | Drug | Duration | Features |
|---|---|---|---|
| Short-acting (quaternary alcohol) | Edrophonium | 10-20 min | Diagnostic only (Tensilon test); IV |
| Medium-acting (carbamates) | Physostigmine | 30 min-2 hr | Crosses BBB; reverses CNS effects |
| Neostigmine | 30 min-2 hr | Does NOT cross BBB; quaternary amine | |
| Pyridostigmine | 3-6 hr | Drug of choice in MG; oral | |
| Rivastigmine | Several hours | Alzheimer's disease | |
| Long-acting (organophosphates) | Ecothiophate | Days-weeks | Eye drops for glaucoma |
- Organophosphates: Parathion, Malathion (pesticides); Sarin, Tabun, VX (nerve agents)
- Bind covalently → "Aging" occurs → permanent inactivation
Mechanism of Reversible AChE Inhibitor (Neostigmine):
- Neostigmine binds the anionic and esteratic sites of AChE
- Forms a carbamylated enzyme complex
- Enzyme is temporarily inactivated (hydrolysis is 1000x slower than with ACh)
- Enzyme gradually regenerates (reversible)
- Net effect: ACh accumulates → enhanced cholinergic effects
Uses of Reversible AChE Inhibitors:
| Drug | Uses |
|---|---|
| Neostigmine | Myasthenia gravis (parenteral), reversal of non-depolarizing NMJ blockade, post-operative ileus/urinary retention |
| Pyridostigmine | Myasthenia gravis (oral - drug of choice), nerve agent prophylaxis (military) |
| Edrophonium | Diagnosis of MG (Tensilon test), differentiating myasthenic vs cholinergic crisis |
| Physostigmine | Glaucoma (eye drops), reversal of anticholinergic (atropine) overdose |
| Rivastigmine, Donepezil, Galantamine | Alzheimer's disease (improve cognitive symptoms) |
| Ecothiophate | Open-angle glaucoma (long-acting eye drops) |
ANS-C4: Classification and Uses of Anticholinergic Drugs
Classification:
- Atropine (from Atropa belladonna)
- Scopolamine (Hyoscine) - from Hyoscyamus
- Homatropine
- Ipratropium (Quaternary - inhaled, does not cross BBB)
- Tiotropium (Long-acting, COPD)
- Glycopyrrolate (Quaternary - no CNS effects)
- Dicyclomine (antispasmodic - IBS)
- Oxybutynin (urinary incontinence)
- Solifenacin, Tolterodine (overactive bladder)
- Benztropine, Trihexyphenidyl (Parkinson's disease)
- Pirenzepine (M1 selective - peptic ulcer - largely obsolete)
Pharmacological Effects of Anticholinergics:
MNEMONIC: "Can't See, Can't Spit, Can't Pee, Can't Shit, Can't Sweat + Mad as a Hatter"
Can't See → Mydriasis, cycloplegia (blurred near vision)
Can't Spit → Dry mouth (decreased salivation)
Can't Pee → Urinary retention (relaxes detrusor, contracts sphincter)
Can't Shit → Constipation (↓ GI motility)
Can't Sweat → Dry, flushed, hot skin (inhibit sweat glands)
Mad as Hatter → CNS excitation at high doses (delirium, hallucinations)
+ Tachycardia (block M2 receptors in SA node)
Uses of Anticholinergic Drugs:
| Indication | Drug Used |
|---|---|
| Preanesthetic medication | Atropine/Glycopyrrolate (↓ secretions, prevents bradycardia) |
| Organophosphate poisoning | Atropine (antidote for muscarinic symptoms) |
| Bradycardia | Atropine IV |
| Irritable Bowel Syndrome | Dicyclomine |
| Peptic ulcer | Pirenzepine (M1 selective) - rarely used now |
| COPD/Asthma | Ipratropium, Tiotropium (inhaled bronchodilators) |
| Motion sickness | Scopolamine (transdermal patch) |
| Parkinson's disease | Benztropine, Trihexyphenidyl |
| Urinary incontinence | Oxybutynin, Solifenacin, Tolterodine |
| Ophthalmology (mydriasis/cycloplegia) | Atropine, Homatropine (eye drops) |
| Antidote for AChE inhibitor overdose | Atropine |
Contraindications:
- Glaucoma (narrow-angle) - pupil dilation blocks aqueous drainage
- BPH - urinary retention worsened
- Pyloric stenosis, hiatus hernia
- Tachyarrhythmias
- Myasthenia gravis
ANS-C5: Uses of Atropine
Dose-Dependent Effects:
0.5 mg → Slight bradycardia (paradoxical - blocks presynaptic M1)
Decreased sweating/salivation
1 mg → Dry mouth, tachycardia
2 mg → Tachycardia, mydriasis, cycloplegia, difficulty swallowing
5 mg → All above + urinary retention, restlessness, fatigue
10 mg+ → CNS: Delirium, hallucinations, hyperthermia, coma
Clinical Uses of Atropine:
| Use | Dose/Route | Mechanism |
|---|---|---|
| Organophosphate poisoning | 1.2-3 mg IV, repeated till atropinization | Blocks muscarinic ACh receptors |
| Preanesthetic medication | 0.6 mg IM/SC | ↓ secretions, prevents laryngospasm/bradycardia |
| Sinus bradycardia | 0.5-1 mg IV | Blocks M2 (vagal) → ↑ HR |
| Heart block (AV block) | 0.5-1 mg IV | Vagolytic → improves conduction |
| During CPR | 1 mg IV | Vagolytic effect |
| Reversal of NMJ blockade | With neostigmine (prevents bradycardia) | Counteracts muscarinic SE of neostigmine |
| Ophthalmology | 1% eye drops | Mydriasis + cycloplegia (for refraction, iritis) |
| Antidote for AChE inhibitor toxicity | High dose IV | Muscarinic receptor blockade |
| Antispasmodic (renal/biliary colic) | 0.6 mg SC/IM | Relaxes smooth muscle |
| Excess vagal tone | Vagolytic |
SECTION 2: ADRENERGIC / SYMPATHETIC SYSTEM
ANS-A1: Therapeutic Uses of Adrenaline (Epinephrine)
ADRENERGIC RECEPTOR ACTIONS OF ADRENALINE:
┌──────────────────────────────────────────────────────┐
│ Receptor │ Location │ Effect │
├──────────┼──────────────────┼─────────────────────────┤
│ α1 │ Blood vessels │ Vasoconstriction │
│ │ Pupil (dilator) │ Mydriasis │
│ α2 │ Presynaptic │ ↓ NE release (autoreceptor)│
│ β1 │ Heart │ ↑ HR, ↑ Contractility │
│ β2 │ Bronchi │ Bronchodilation │
│ │ Blood vessels │ Vasodilation │
│ │ Mast cells │ ↓ Mediator release │
│ │ Uterus │ Relaxation │
│ │ Liver/muscle │ Glycogenolysis │
└──────────────────────────────────────────────────────┘
Uses of Adrenaline:
| Indication | Dose/Route | Rationale |
|---|---|---|
| Anaphylactic shock (DRUG OF CHOICE) | 0.5 mg IM (1:1000), repeat 5 min | α1: vasoconstriction; β1: cardiac support; β2: bronchodilation + ↓ mast cell degranulation |
| Cardiac arrest | 1 mg IV (1:10,000) every 3-5 min (during CPR) | β1: cardiac stimulation; α1: coronary perfusion |
| Bronchial asthma (acute) | SC/nebulized | β2: bronchodilation (salbutamol now preferred) |
| Local anesthetic adjuvant | 1:200,000 | α1: vasoconstriction → ↓ bleeding, prolonged analgesia, ↓ systemic toxicity |
| Open angle glaucoma | 1-2% eye drops | ↓ aqueous humor production + ↑ outflow |
| Haemostasis in surgery | Topical | α1: local vasoconstriction |
| Nasal decongestant | Topical | α1: mucosal vasoconstriction |
| Heart block | IV infusion | Cardiac stimulation |
| Croup | Nebulized (racemic epinephrine) | β2: bronchodilation; α1: ↓ mucosal edema |
ANS-A2: Dopamine
Dose-Dependent Effects (Classic):
DOPAMINE: DOSE-DEPENDENT EFFECTS
LOW DOSE (1-5 μg/kg/min)
↓
D1 receptors (renal, mesenteric, coronary vessels)
→ Vasodilation → ↑ renal blood flow, ↑ urine output, ↑ Na+ excretion
("Renal dose dopamine")
MEDIUM DOSE (5-10 μg/kg/min)
↓
β1 receptors (heart)
→ ↑ HR, ↑ contractility, ↑ cardiac output
(Inotropic effect)
HIGH DOSE (>10 μg/kg/min)
↓
α1 receptors (blood vessels)
→ Vasoconstriction → ↑ BP (pressor effect)
(Similar to noradrenaline)
Therapeutic Uses of Dopamine:
| Use | Dose | Rationale |
|---|---|---|
| Cardiogenic shock | Medium-high dose (5-20 μg/kg/min) | Inotropic + pressor effects |
| Septic shock | Medium-high dose | Vasopressor |
| Acute heart failure with hypotension | Low-medium dose | Inotropic, ↑ renal perfusion |
| Adjuvant in renal failure with hypotension | Low dose | D1-mediated renal vasodilation |
D2 Agonists (separate class):
- Bromocriptine, Cabergoline - Parkinson's disease, hyperprolactinaemia
- Pramipexole, Ropinirole - Parkinson's disease
ANS-A3: Uses of Alpha Blockers
Classification:
- Phentolamine (competitive/reversible) - acute hypertensive crises, pheochromocytoma surgery
- Phenoxybenzamine (non-competitive/irreversible) - pheochromocytoma
- Prazosin (short-acting) - hypertension
- Terazosin, Doxazosin (long-acting) - hypertension, BPH
- Tamsulosin, Silodosin (uro-selective α1A blockers) - BPH (minimal hypotension)
- Alfuzosin - BPH
- Yohimbine (experimental, erectile dysfunction)
Uses of Alpha Blockers:
| Indication | Drug | Mechanism |
|---|---|---|
| Hypertension | Prazosin, Doxazosin | α1 blockade → vasodilation → ↓ BP; "First-dose hypotension" is a problem |
| Benign Prostatic Hypertrophy | Tamsulosin, Alfuzosin, Terazosin | Block α1A in prostatic smooth muscle → ↓ urethral resistance → ↑ urine flow |
| Pheochromocytoma (preoperative) | Phenoxybenzamine → then Phentolamine | Prevents hypertensive crisis during tumor manipulation |
| Peripheral vascular disease (Raynaud's) | Prazosin | α1 blockade → vasodilation in extremities |
| Heart failure | Prazosin (adjunct) | Reduces afterload |
| Open angle glaucoma | Brimonidine (α2 agonist - different) | ↓ aqueous production |
| Benign essential tremor | Not primary use |
ANS-A4: Use of Nitrates and Beta-Blockers in Angina Pectoris
Pathophysiology of Angina:
ANGINA = Myocardial O2 Demand > Supply
Determinants of O2 DEMAND: Determinants of O2 SUPPLY:
• Heart rate • Coronary blood flow
• Contractility • O2 carrying capacity
• Wall tension (preload + • Duration of diastole
afterload)
NITRATES in Angina:
Nitrate → Converted to Nitric Oxide (NO) in vascular smooth muscle
↓
Activates Guanylyl cyclase → ↑ cGMP → PKG activation
↓
Myosin light chain dephosphorylation → Smooth muscle RELAXATION
↓
VENODILATION (main) ARTERIAL dilation (at higher doses)
↓ ↓
↓ Preload (venous return) ↓ Afterload
↓ Ventricular filling pressure ↓ Systemic vascular resistance
↓ Wall tension ↓ BP
↓
↓ Myocardial O2 demand
+ Coronary vasodilation (relieving spasm)
↓
RELIEF OF ANGINA
| Nitrate | Route | Onset | Duration | Use |
|---|---|---|---|---|
| GTN sublingual | SL tab/spray | 1-2 min | 15-30 min | Acute angina attack |
| GTN transdermal | Patch | Hours | 24 h | Prophylaxis (12h on/12h off to prevent tolerance) |
| GTN IV | IV infusion | Seconds | During infusion | Unstable angina, LVF |
| ISDN oral | Oral | 30-60 min | 4-6 h | Prophylaxis |
| ISMN oral | Oral | 30-60 min | 10-14 h | Prophylaxis |
BETA-BLOCKERS in Angina:
β1 blockade (heart)
↓
↓ Heart Rate ↓ Contractility
↓ ↓
↓ O2 Demand ↓ O2 Demand
↓
Prolongs diastole → ↑ time for coronary perfusion → ↑ O2 supply
↓
ANTI-ANGINAL EFFECT
(Especially useful in exercise-induced angina)
| Property | Beta-Blockers in Angina |
|---|---|
| Best for | Stable exertional angina, Post-MI angina |
| Disadvantage | May cause coronary vasospasm (worsen vasospastic/Prinzmetal angina) |
| Not used alone for | Vasospastic (Prinzmetal) angina - CCBs preferred |
| Combined with | Nitrates (offset reflex tachycardia from nitrates) |
Nitrate alone → ↓ BP → Reflex tachycardia (worsens angina)
Beta-blocker alone → ↑ LV size/preload (bad)
COMBINATION → Beta-blocker prevents reflex tachycardia
Nitrate prevents ↑ preload from beta-blocker
→ SYNERGISTIC anti-anginal effect
ANS-A5: Cardiac and Non-Cardiac Uses of Beta-Blockers
Classification of Beta-Blockers:
| Group | Drug | Features |
|---|---|---|
| Non-selective (β1+β2) | Propranolol, Nadolol, Timolol, Sotalol | Block both β1 and β2 |
| Cardioselective (β1) | Atenolol, Metoprolol, Bisoprolol, Nebivolol | Mainly β1 at low doses |
| With ISA | Pindolol, Acebutolol | Partial agonist activity - less bradycardia at rest |
| α+β blocker | Labetalol, Carvedilol | Additional α1 blockade - vasodilation |
| β1 blocker + NO release | Nebivolol | Vasodilatory |
CARDIAC Uses:
| Condition | Drug | Rationale |
|---|---|---|
| Hypertension | Atenolol, Bisoprolol | ↓ CO, ↓ renin release, ↓ central sympathetic tone |
| Angina pectoris | Propranolol, Atenolol | ↓ HR, ↓ contractility → ↓ O2 demand |
| Post-MI (secondary prevention) | Propranolol, Metoprolol | ↓ re-infarction, ↓ sudden cardiac death |
| Arrhythmias (SVT, AF, VT) | Propranolol, Esmolol, Metoprolol | ↓ AV nodal conduction, ↓ automaticity |
| Chronic heart failure | Carvedilol, Bisoprolol, Metoprolol succinate | ↓ sympathetic-mediated cardiac remodeling (start LOW, go SLOW) |
| Hypertrophic obstructive cardiomyopathy (HOCM) | Propranolol | ↓ outflow obstruction |
NON-CARDIAC Uses:
| Condition | Drug | Rationale |
|---|---|---|
| Hyperthyroidism / Thyroid storm | Propranolol | ↓ Tachycardia; blocks peripheral T4→T3 conversion |
| Pheochromocytoma | Propranolol (with α-blocker) | ↓ Tachycardia (NEVER give β-blocker alone - unopposed α → hypertensive crisis) |
| Essential tremor | Propranolol | ↓ Peripheral β2 receptor-mediated tremor |
| Portal hypertension / Esophageal varices | Propranolol, Nadolol | ↓ Portal pressure → ↓ variceal bleeding |
| Migraine prophylaxis | Propranolol, Timolol | ↓ Catecholamine-triggered vasodilation |
| Anxiety / Performance anxiety | Propranolol | Blocks peripheral somatic symptoms (palpitations, tremor) |
| Open angle glaucoma | Timolol (eye drops) | ↓ Aqueous humor production |
| Phaeochromocytoma (perioperative) | After α-blocker | ↓ Cardiac effects |
Contraindications of Beta-Blockers:
- Asthma/COPD (β2 blockade → bronchospasm)
- Uncontrolled heart failure
- AV block (2nd/3rd degree)
- Bradycardia
- Pheochromocytoma (without prior α-blockade)
- Peripheral arterial disease (worsens claudication)
ANS-A6: Cardiac and Non-Cardiac Uses of Propranolol
CARDIAC Uses:
| Indication | Dose | Notes |
|---|---|---|
| Hypertension | 40-160 mg BD | Long-term management |
| Angina pectoris | 40-80 mg TDS | Reduces O2 demand |
| Arrhythmias (SVT, AF rate control) | 10-40 mg TDS | ↓ AV nodal conduction |
| Post-MI prophylaxis | 20-40 mg QID | ↓ Sudden cardiac death |
| HOCM | 40-80 mg TDS | ↓ Outflow obstruction |
| Aortic dissection | IV | ↓ dP/dt |
NON-CARDIAC Uses:
| Indication | Notes |
|---|---|
| Hyperthyroidism | Controls tachycardia, tremor; blocks T4→T3 conversion |
| Essential tremor | Drug of choice |
| Migraine prophylaxis | Drug of choice; reduces frequency |
| Portal hypertension | Reduces variceal bleeding |
| Anxiety (performance) | Controls somatic symptoms |
| Pheochromocytoma | Only AFTER alpha-blocker given |
| Tetralogy of Fallot (cyanotic spells) | Relaxes RV outflow obstruction |
ANS-A7: Drug Therapy of Open Angle Glaucoma
Pathophysiology:
AQUEOUS HUMOR FLOW:
Ciliary body (PRODUCTION) → Posterior chamber → Pupil →
Anterior chamber → Trabecular meshwork → Canal of Schlemm →
Episcleral veins (DRAINAGE)
OPEN ANGLE GLAUCOMA: Drainage through trabecular meshwork is IMPAIRED
→ ↑ IOP (Normal IOP = 10-21 mmHg) → Optic nerve damage → Field loss
Drug Treatment - Opens Angle Glaucoma:
GOALS: ↓ Aqueous Production OR ↑ Aqueous Outflow (or both)
| Drug Class | Drug | MOA | Route |
|---|---|---|---|
| β-blockers | Timolol (0.5%), Betaxolol (β1 selective) | ↓ Aqueous production from ciliary epithelium | Eye drops |
| Prostaglandin analogues (First-line) | Latanoprost (0.005%), Bimatoprost, Travoprost | ↑ Uveoscleral outflow of aqueous | Evening eye drops |
| α2 agonists | Brimonidine (0.2%) | ↓ Aqueous production + ↑ uveoscleral outflow | Eye drops |
| Carbonic anhydrase inhibitors | Dorzolamide (topical), Acetazolamide (oral/IV) | ↓ Aqueous production (inhibits CA in ciliary body) | Eye drops / oral |
| Cholinomimetics (miotics) | Pilocarpine (1-4%) | ↑ Trabecular outflow (ciliary muscle contraction opens drainage) | Eye drops |
| Rho-kinase inhibitor | Netarsudil | ↑ Trabecular outflow | Eye drops |
ANS-A8: Drug Therapy of Acute Congestive (Angle-Closure) Glaucoma
Pathophysiology:
NARROW-ANGLE GLAUCOMA:
Pupillary block → Iris bows forward (iris bombe) →
Occludes angle → Aqueous cannot drain → Acute ↑↑ IOP
Precipitated by: Mydriasis (dim light, anticholinergics)
Clinical Features:
- Sudden severe eye pain
- Nausea/vomiting
- Halos around lights
- Blurred vision
- Fixed mid-dilated pupil
- Congested (red) eye
- Very high IOP (>40-50 mmHg)
Emergency Treatment:
- Acetazolamide 500 mg IV (or oral if tolerated) - carbonic anhydrase inhibitor → ↓ aqueous production rapidly
- Mannitol 1-2 g/kg IV (20% solution) - osmotic agent → draws aqueous into plasma
- Glycerol 1-1.5 g/kg oral - osmotic agent (alternative to mannitol)
- Pilocarpine 2-4% eye drops every 15 min (after IOP has started to fall) - miosis → pulls iris away from angle → opens drainage
- Topical steroid eye drops
- Laser peripheral iridotomy or surgical iridectomy - creates new drainage pathway, curative
ACUTE GLAUCOMA TREATMENT SUMMARY
───────────────────────────────────────────────
EMERGENCY (↓ IOP):
Acetazolamide 500 mg IV
+ Mannitol IV (if very high IOP)
↓
MIOSIS (open angle):
Pilocarpine 2-4% eye drops
↓
TOPICAL STEROIDS (↓ inflammation)
↓
DEFINITIVE: Laser iridotomy
───────────────────────────────────────────────
AVOID: Anticholinergics (dilate pupil → worsen)
Sympathomimetics (mydriasis → worsen)
ANS-A9: Drug Therapy of Benign Prostatic Hypertrophy (BPH)
Pathophysiology:
BPH = Benign enlargement of prostate → Bladder outlet obstruction
Symptoms: Hesitancy, weak stream, dribbling, frequency, nocturia
TWO COMPONENTS:
1. STATIC (anatomical enlargement) → 5α-reductase inhibitors
2. DYNAMIC (smooth muscle tone) → α1-blockers
Drug Treatment:
| Drug | Selectivity | Notes |
|---|---|---|
| Tamsulosin | α1A (uro-selective) | Most commonly used; minimal cardiovascular effects; no need for dose titration |
| Silodosin | α1A highly selective | Very uro-selective; minimal hypotension |
| Alfuzosin | α1 | Less BP effect |
| Doxazosin | α1 (non-selective) | Also treats hypertension; postural hypotension |
| Terazosin | α1 (non-selective) | Also treats hypertension |
| Drug | Notes |
|---|---|
| Finasteride | 5 mg/day; blocks conversion of testosterone → DHT; shrinks prostate over 3-6 months |
| Dutasteride | Blocks both 5α-reductase type 1 and 2 |
- Alpha-blocker + 5α-reductase inhibitor (e.g., Tamsulosin + Dutasteride = Duodart)
- Best for large prostates, high symptom scores
- Combination superior to either alone for long-term outcomes
- Tadalafil 5 mg/day - approved for BPH ± erectile dysfunction
- Relaxes smooth muscle via ↑ cGMP pathway
- Solifenacin, Oxybutynin (if predominant storage symptoms/overactive bladder)
- CAUTION: Can cause urinary retention
BPH TREATMENT OVERVIEW
─────────────────────────────────────────────────────
Dynamic symptoms → α1-BLOCKERS (Tamsulosin)
Fast onset; symptom relief in days
↕
Static (large prostate) → 5α-RI (Finasteride/Dutasteride)
Slow onset; shrinks gland 3-6 months
↕
COMBINATION → Best for symptomatic large prostates
─────────────────────────────────────────────────────
Surgery (TURP) if drugs fail
─────────────────────────────────────────────────────
Quick Exam Orientation - ANS Topics Covered
- ANS-C1 Organophosphorus Poisoning - SLUDGE symptoms, Atropine (muscarinic antidote) + Pralidoxime (AChE reactivator, before aging)
- ANS-C2 Myasthenia Gravis - anti-AChR antibodies, Pyridostigmine (drug of choice), crisis management
- ANS-C3 Anticholinesterases - Classification (reversible: Edrophonium/Neostigmine/Pyridostigmine; irreversible: OPs) + mechanism of reversible inhibitors
- ANS-C4 Anticholinergic Drugs - Classification + mnemonic "Can't See/Spit/Pee/Shit/Sweat"
- ANS-C5 Uses of Atropine - dose-dependent effects + all clinical uses
- ANS-A1 Adrenaline - receptor-wise actions + all therapeutic uses including anaphylaxis, cardiac arrest, LA adjuvant
- ANS-A2 Dopamine - dose-dependent effects (low D1/renal, mid β1/inotrope, high α1/pressor) + clinical uses
- ANS-A3 Alpha Blockers - classification (Phentolamine, Prazosin, Tamsulosin) + uses including BPH, pheochromocytoma, hypertension
- ANS-A4 Nitrates + Beta-Blockers in Angina - mechanism diagrams, nitrate tolerance, synergistic combination
- ANS-A5 Cardiac + Non-cardiac Uses of Beta-Blockers - full classification table
- ANS-A6 Propranolol - cardiac + non-cardiac uses with doses
- ANS-A7 Open Angle Glaucoma - prostaglandin analogues (first-line), Timolol, Pilocarpine, Acetazolamide
- ANS-A8 Acute Congestive Glaucoma - emergency: Acetazolamide IV + Mannitol → Pilocarpine → Laser iridotomy
- ANS-A9 BPH - alpha-blockers (dynamic, fast) vs 5α-reductase inhibitors (static, slow) + combination therapy
High-yield exam tip: OP poisoning management (Atropine + Pralidoxime), MG treatment (Pyridostigmine), beta-blocker classification, and glaucoma drug mechanisms are the most frequently tested questions in this section.