1. Complete answers for all questions in the uploaded Section-2 paper,
2. Only selected questions (tell me question numbers), or
3. Model exam-ready notes (high-yield, pointwise, with headings) for each topic?

SECTION-2: Complete Answers (Pharmacology)

Q-2 (A) Structured long question

1) Aminoglycosides: classification, mechanism, therapeutic uses, adverse effects

A. Classification of aminoglycosides

1. Streptomycin group
   • Streptomycin
   • Dihydrostreptomycin (obsolete)
2. Neomycin group
   • Neomycin
   • Framycetin
   • Paromomycin
3. Gentamicin group
   • Gentamicin
   • Tobramycin
   • Amikacin
   • Netilmicin
   • Sisomicin
4. Others
   • Kanamycin
   • Spectinomycin (aminocyclitol, related but not a classic aminoglycoside)

• Systemic use: gentamicin, amikacin, tobramycin, netilmicin, streptomycin
• Topical/oral non-absorbable use: neomycin, framycetin, paromomycin

B. Mechanism of action

1. Entry into bacteria
   • Initial passive diffusion through outer membrane (in gram-negative bacilli).
   • Active oxygen-dependent transport across cytoplasmic membrane.
   • Hence, they are ineffective against anaerobes (no oxygen-dependent uptake).
2. Ribosomal action (30S subunit)
   • Irreversibly bind to 30S ribosome (16S rRNA + S12 protein region).
   • Cause:
     • Inhibition of initiation complex
     • Misreading of mRNA (abnormal proteins)
     • Breakup of polysomes into nonfunctional monosomes
3. Post-antibiotic effect
   • Persistent suppression of bacterial growth even after drug level falls below MIC.
4. Concentration-dependent killing
   • Higher peak concentration gives better killing.
5. Synergy
   • With cell wall-active drugs (penicillins/vancomycin) due to enhanced entry, e.g., enterococcal endocarditis regimens.

C. Important therapeutic uses

1. Serious aerobic gram-negative infections
   • Septicemia, complicated UTI, hospital-acquired pneumonia, intra-abdominal infections (in combination).
   • Drugs: gentamicin, amikacin, tobramycin.
2. Pseudomonas infections
   • Tobramycin/amikacin (often with antipseudomonal beta-lactam).
3. Tuberculosis
   • Streptomycin as second-line/adjunct in selected cases.
4. Plague, tularemia, brucellosis
   • Streptomycin or gentamicin depending on protocol.
5. Enterococcal/streptococcal endocarditis (synergy)
   • Gentamicin + beta-lactam/vancomycin.
6. Neonatal sepsis
   • Gentamicin or amikacin with ampicillin/cephalosporin as per policy.
7. Bowel sterilization/pre-op gut decontamination
   • Oral neomycin (historical/selected use).
8. Hepatic encephalopathy (rare now)
   • Oral neomycin (largely replaced by safer agents).
9. Topical infections
   • Neomycin/framycetin in skin, eye, ear preparations.
10. Protozoal infection

• Paromomycin in intestinal amoebiasis/cryptosporidiosis; visceral leishmaniasis (in some regimens).

D. Adverse effects

1. Ototoxicity (often irreversible)
   • Cochlear: tinnitus, hearing loss (more with amikacin, kanamycin, neomycin)
   • Vestibular: vertigo, ataxia, nystagmus (more with streptomycin, gentamicin)
   • Risk factors: prolonged therapy, high trough levels, renal failure, loop diuretics, vancomycin, elderly.
2. Nephrotoxicity (usually reversible)
   • Acute tubular injury, rising creatinine.
   • More with neomycin, gentamicin; less with netilmicin (comparatively).
3. Neuromuscular blockade
   • Curare-like effect; may cause respiratory depression (rare).
   • More risk in myasthenia gravis or with anesthetics.
   • Treated with calcium salts/neostigmine and ventilatory support.
4. Hypersensitivity
   • Rash, fever (uncommon); contact dermatitis with topical neomycin.
5. Fetal toxicity
   • Potential congenital ototoxicity; avoid in pregnancy unless essential.
6. Other
   • Superinfection with prolonged use, pain at injection site.

E. Resistance mechanisms (brief add-on for completeness)

• Enzymatic inactivation (acetylation, adenylation, phosphorylation) - most common
• Decreased uptake/porin changes
• Altered ribosomal binding site
• Efflux mechanisms

2) Bronchial asthma: pathophysiology, drug classification, rationale of salmeterol + fluticasone in chronic asthma

A. Brief pathophysiology of bronchial asthma

1. Airway inflammation
   • Mast cells, eosinophils, Th2 lymphocytes, cytokines (IL-4, IL-5, IL-13).
2. Mediator release
   • Histamine, leukotrienes, prostaglandins cause bronchoconstriction, mucosal edema, mucus hypersecretion.
3. Airway hyperreactivity
   • Exaggerated bronchoconstrictor response to allergens, infections, cold air, exercise, irritants.
4. Airflow limitation
   • Bronchospasm + edema + mucus plugging.
5. Airway remodeling in chronic disease
   • Subepithelial fibrosis, smooth muscle hypertrophy, goblet cell hyperplasia, reduced reversibility over time.

B. Classification of drugs used in bronchial asthma

I. Bronchodilators (relievers)

1. Beta2 agonists
   • SABA: salbutamol, terbutaline
   • LABA: salmeterol, formoterol (not as monotherapy in persistent asthma)
2. Anticholinergics
   • Ipratropium (SAMA), tiotropium (LAMA add-on)
3. Methylxanthines
   • Theophylline, aminophylline (limited due to narrow therapeutic index)

II. Anti-inflammatory / controller drugs

1. Corticosteroids
   • Inhaled: beclomethasone, budesonide, fluticasone
   • Systemic: prednisolone, hydrocortisone (acute severe cases)
2. Leukotriene pathway inhibitors
   • Montelukast, zafirlukast (CysLT1 blockers)
   • Zileuton (5-lipoxygenase inhibitor)
3. Mast cell stabilizers
   • Cromolyn, nedocromil (less used now)
4. Biologics for severe asthma
   • Anti-IgE: omalizumab
   • Anti-IL5/IL5R: mepolizumab, benralizumab
   • Anti-IL4R: dupilumab

C. Rationale for salmeterol + fluticasone in chronic asthma

1. Different and complementary actions
   • Salmeterol: prolonged beta2 stimulation -> bronchodilation, symptom relief (especially nocturnal/exercise symptoms).
   • Fluticasone: potent anti-inflammatory effect -> suppresses airway inflammation, reduces hyperresponsiveness and exacerbations.
2. Steroid-sparing and better control
   • Combination improves lung function and symptom control better than increasing ICS dose alone in many patients.
3. Prevention of exacerbations
   • ICS reduces risk of severe attacks; LABA improves day/night symptom profile.
4. Improved adherence
   • Single inhaler combination improves compliance.
5. Pharmacologic synergy
   • Corticosteroids upregulate beta2 receptors and reduce desensitization.
   • Beta2 agonists may facilitate glucocorticoid receptor nuclear translocation.
6. Important safety principle
   • LABA should not be used alone in asthma due to increased risk of severe outcomes; must be combined with ICS.

Q-2 (B) Attempt any two (complete all given here)

1) Case of seasonal allergic rhinitis treated with levocetirizine

a) Rationale for prescribing levocetirizine

1. Selective H1 receptor blockade
   • Antagonizes effects of histamine released from mast cells.
2. Effective control of early allergic symptoms
   • Reduces sneezing, itching, rhinorrhea, ocular symptoms.
3. Second-generation antihistamine
   • Less sedating than first-generation drugs due to poor CNS penetration.
4. Long duration
   • Once-daily dosing improves compliance.
5. Good tolerability
   • Minimal anticholinergic adverse effects compared with first-generation agents.
6. Active enantiomer of cetirizine
   • Potent H1 activity at low dose.

b) Uses of antihistamines other than allergic conditions

1. Motion sickness and vestibular disorders
   • Promethazine, dimenhydrinate, meclizine.
2. Antiemetic use
   • Promethazine in nausea/vomiting (including drug-induced, postoperative).
3. Sedation / short-term insomnia
   • Diphenhydramine, promethazine.
4. Pre-anesthetic medication
   • Sedative + antiemetic + anticholinergic benefits (promethazine).
5. Symptomatic relief in common cold
   • Decrease sneezing/rhinorrhea (limited and symptomatic benefit).
6. Drug-induced parkinsonism/acute dystonia
   • Diphenhydramine (anticholinergic property).
7. Pruritus of non-allergic origin
   • Symptomatic itch suppression due to sedative action.
8. Cough suppression adjunct (some combinations)
   • Older formulations.
9. Appetite stimulation (selected agents)
   • Cyproheptadine.
10. Migraine prophylaxis (rare/adjunct)

• Cyproheptadine in selected patients.

2) Parkinsonism treated with levodopa 100 mg + carbidopa 25 mg

a) Rationale of levodopa + carbidopa combination

1. Levodopa is dopamine precursor
   • Crosses blood-brain barrier and converts to dopamine in CNS, improving bradykinesia/rigidity.
2. Problem with levodopa alone
   • Extensive peripheral decarboxylation to dopamine causes:
     • Nausea/vomiting
     • Cardiac arrhythmias, hypotension
     • Less drug reaching brain
3. Carbidopa action
   • Peripheral dopa decarboxylase inhibitor; does not significantly cross BBB.
4. Benefits of combination
   • More levodopa reaches CNS (higher brain availability).
   • Lower levodopa dose needed (about 1/3 to 1/5).
   • Reduced peripheral adverse effects (GI/cardiovascular).
   • Better symptomatic response and tolerability.
5. Dose ratio
   • Common fixed-dose ratio 4:1 (e.g., 100/25 mg), as in this case.

b) ON-OFF effect of levodopa

1. ON phase
   • Good mobility, improved motor performance.
2. OFF phase
   • Sudden return of parkinsonian symptoms (akinesia, rigidity, tremor), often unpredictable.
3. Wearing-off (end-of-dose deterioration)
   • Predictable OFF before next dose due to short plasma half-life and reduced buffering by degenerating nigrostriatal neurons.
4. True ON-OFF phenomenon
   • Abrupt, less predictable shifts unrelated to dosing time in advanced disease.
5. Related dyskinesias
   • Peak-dose choreiform movements may alternate with OFF akinesia.
6. Mechanistic basis
   • Progressive neuronal loss + pulsatile dopaminergic stimulation + short levodopa half-life.
7. Management strategies
   • Increase dosing frequency/smaller divided doses.
   • Add COMT inhibitor (entacapone/opicapone) or MAO-B inhibitor (selegiline/rasagiline/safinamide).
   • Add dopamine agonist (pramipexole/ropinirole/rotigotine).
   • Extended-release formulations, intestinal gel, apomorphine rescue in selected cases.
   • Advanced cases: DBS.

3) P. falciparum malaria case (high fever with chills, smear positive)

a) How to treat this patient

1. Start ACT (Artemisinin-based combination therapy)
   • As per many protocols: Artesunate + mefloquine
     (alternative country-specific ACTs: artemether-lumefantrine, DHA-piperaquine, etc.)
2. Typical regimen (example)
   • Artesunate once daily for 3 days + mefloquine total therapeutic dose split over day 2 and 3 (follow national guideline dosing by body weight).
3. Add single-dose primaquine (where recommended)
   • Gametocytocidal (contraindicated in pregnancy and G6PD deficiency depending on policy).
4. Supportive care
   • Antipyretics (paracetamol), oral fluids, antiemetic if needed.
5. Assess severity at baseline
   • Rule out severe malaria: altered sensorium, repeated vomiting, jaundice with organ dysfunction, acidosis, shock, severe anemia, hypoglycemia, renal failure, pulmonary edema, hyperparasitemia.
6. If severe malaria appears
   • Immediate IV artesunate regimen + intensive supportive management, then switch to full oral ACT course once stable.
7. Follow-up
   • Clinical response and parasite clearance; monitor for treatment failure or complications.

b) Pharmacological basis of artesunate + mefloquine

1. Why combination?
   • Different mechanisms reduce parasite biomass rapidly and prevent resistance emergence.
2. Artesunate
   • Artemisinin derivative; activated by heme-iron in parasite food vacuole.
   • Generates free radicals causing parasite protein/membrane damage.
   • Very rapid action; major reduction in parasite load and fever.
   • Short half-life -> not sufficient alone (recrudescence risk).
3. Mefloquine
   • Blood schizontocide with long half-life.
   • Likely interferes with heme detoxification/parasite membrane function.
   • Slower onset than artesunate but sustained effect clears residual parasites.
4. Combination advantage
   • Fast parasite clearance (artesunate) + prolonged post-treatment suppression (mefloquine).
   • Better cure rates and lower recrudescence than monotherapy.
   • Delays resistance by exposing parasites to two unrelated drugs.
5. Clinical benefit
   • Rapid symptom relief and reduced transmission when coupled with gametocytocidal strategy.
6. Key adverse-effect considerations
   • Artesunate: generally well tolerated.
   • Mefloquine: GI upset, dizziness, neuropsychiatric effects in susceptible individuals; avoid in patients with certain psychiatric/seizure histories.

Q-3 Short notes (any three asked; all four provided)

1) Pre-anesthetic medication

Objectives

1. Anxiolysis, sedation, amnesia
2. Analgesia and reduced anesthetic requirement
3. Antisialagogue and vagolysis where needed
4. Prevention of nausea/vomiting and aspiration
5. Reduction of gastric volume/acidity
6. Prevention of allergic reactions in selected patients

Drugs used

1. Sedative-anxiolytics
   • Benzodiazepines: midazolam, diazepam, lorazepam
2. Opioid analgesics
   • Fentanyl, morphine (selected cases)
3. Anticholinergics
   • Glycopyrrolate, atropine (reduce secretions, prevent vagal bradycardia)
4. Antiemetics
   • Ondansetron, metoclopramide, dexamethasone
5. Anti-aspiration prophylaxis
   • H2 blockers (ranitidine/famotidine), PPIs, non-particulate antacid (sodium citrate), prokinetic (metoclopramide)
6. Others as indicated
   • Antibiotic prophylaxis, bronchodilator inhalation in reactive airway disease

Principles

• Tailor to age, comorbidities, surgery type.
• Avoid over-sedation in elderly/respiratory compromise.
• Time administration appropriately.

2) Antibiotic resistance

Types

1. Natural (intrinsic) resistance
2. Acquired resistance
   • Mutation
   • Gene transfer (plasmids, transposons, integrons via conjugation/transduction/transformation)
3. Cross-resistance among same class drugs
4. Multidrug resistance (MDR)

Mechanisms

1. Drug inactivation (beta-lactamases, aminoglycoside-modifying enzymes)
2. Altered target site (PBPs, ribosomal changes, DNA gyrase mutations)
3. Reduced permeability (porin loss)
4. Efflux pumps
5. Bypass pathways / target protection
6. Biofilm-related tolerance

Causes promoting resistance

• Inappropriate prescribing (viral illness, wrong spectrum)
• Inadequate dose/duration, poor adherence
• OTC misuse and self-medication
• Agricultural antibiotic overuse
• Poor infection control and sanitation

Clinical impact

• Treatment failure, prolonged illness/hospital stay
• Increased mortality and cost
• Need for toxic or expensive reserve drugs

Prevention/Control

1. Antimicrobial stewardship
2. Culture-guided therapy and de-escalation
3. Correct dose and duration
4. Infection prevention (hand hygiene, isolation, vaccination)
5. Surveillance and resistance reporting
6. Restrict non-therapeutic use in livestock

3) Beta-lactamase inhibitors

Agents

1. Classical suicide inhibitors
   • Clavulanic acid
   • Sulbactam
   • Tazobactam
2. Newer inhibitors
   • Avibactam
   • Relebactam
   • Vaborbactam

Mechanism

• Bind and inhibit beta-lactamases (some irreversible, some reversible covalent), thereby restoring activity of companion beta-lactam.

Common combinations

• Amoxicillin + clavulanate
• Ampicillin + sulbactam
• Piperacillin + tazobactam
• Ceftazidime + avibactam
• Meropenem + vaborbactam
• Imipenem + relebactam

Spectrum concept

• Classical inhibitors mainly inhibit many plasmid-mediated class A beta-lactamases.
• Newer molecules broaden inhibition to include difficult enzymes (e.g., KPC for avibactam/vaborbactam combinations), but not all carbapenemases (e.g., metallo-beta-lactamases not inhibited by avibactam).

Clinical uses

• Mixed infections, community and hospital infections where beta-lactamase producing organisms are likely.
• Serious MDR gram-negative infections with newer combinations as per sensitivity and stewardship policy.

Adverse effects

• Mostly those of partner beta-lactam: hypersensitivity, GI upset, diarrhea, candidiasis, hepatic enzyme rise (some combinations).

4) Lignocaine (Lidocaine)

Mechanism of action

• Blocks voltage-gated sodium channels from intracellular side (preferentially in open/inactivated state), preventing action potential initiation and propagation.
• Use-dependent block in rapidly firing tissues.

Pharmacological actions

1. Local anesthesia
   • Surface, infiltration, field block, nerve block, epidural (not preferred for spinal hyperbaric compared with bupivacaine in many settings)
2. Cardiac
   • Suppresses ventricular ectopic activity, especially in ischemic myocardium.

Uses

1. Local anesthetic in minor surgical/dental/ENT procedures
2. Topical anesthesia (mucosa, airway instrumentation)
3. IV regional anesthesia (with caution)
4. Ventricular arrhythmias (especially post-MI, digitalis-induced ventricular arrhythmias; now selective use)

Pharmacokinetics (high-yield)

• Rapid onset, intermediate duration.
• Hepatic metabolism; active metabolites possible.
• Often combined with adrenaline to prolong action and reduce systemic absorption (except end-artery areas depending on preparation and protocol).

Adverse effects

1. CNS toxicity: circumoral numbness, tinnitus, metallic taste, tremor, seizures, CNS depression
2. CV toxicity: hypotension, myocardial depression, arrhythmias (usually at high plasma levels)
3. Local reactions and rare hypersensitivity (less common than ester LAs)

Contraindications/caution

• Severe heart block without pacemaker (for antiarrhythmic use)
• Severe hepatic dysfunction (dose adjustment)
• Avoid intravascular injection during local use (aspiration test mandatory)

1. a handwritten-style short exam sheet,
2. a 5-mark/10-mark point template, or
3. a last-minute viva rapid revision table.

1. Chronic bronchitis (COPD spectrum)
   • Chronic productive cough, especially morning sputum, common in smokers/pollution exposure.
2. Bronchiectasis
   • Chronic cough with daily sputum, often larger volume in morning due to overnight pooling.
3. Upper airway cough syndrome (post-nasal drip) / chronic sinusitis
   • Night pooling of secretions, morning cough with mucus.
4. Gastroesophageal reflux-related cough
   • Worse after lying down or on waking.
5. Asthma (especially cough-variant)
   • Night/early morning cough; sputum can occur in some patients.
6. Pulmonary tuberculosis (important to exclude in chronic cough >2–3 weeks in high prevalence settings)
   • Especially if fever, weight loss, night sweats, blood in sputum, contact history.
7. Heart failure / pulmonary edema (classically frothy sputum, often pink in acute edema)
   • Consider if breathlessness, orthopnea, leg swelling, cardiac history.
8. Chronic respiratory infection or less commonly lung malignancy
   • Particularly if age >40, smoking, weight loss, blood in sputum.

What to do next (important)

• Chest X-ray
• Sputum test (including AFB/GeneXpert where TB risk exists)
• CBC, CRP
• Spirometry
• If indicated: HRCT chest, ENT evaluation, ECG/echo (if cardiac symptoms)

Red flags needing urgent care now

• Coughing blood
• Breathlessness at rest
• Chest pain
• Fever with worsening sputum
• Weight loss/night sweats
• Oxygen saturation low, confusion, or severe weakness

1. Call emergency services immediately.
2. Keep patient sitting upright.
3. Loosen tight clothing.
4. Do not give food or drink.
5. If wheezing/asthma history and inhaler available: give reliever inhaler (salbutamol) with spacer.
6. If oxygen available, give oxygen.
7. If patient becomes unresponsive and not breathing normally, start CPR.

• Severe asthma attack
• Acute pulmonary edema/heart failure
• Airway obstruction
• Severe pneumonia
• Pneumothorax
• Massive pulmonary embolism
• Stroke affecting speech (if true inability to produce words)

• If “unable to speak” means breathless and can only say 1–2 words, this suggests severe respiratory distress.
• If breathing is okay but speech suddenly abnormal/slurred, think stroke and activate stroke emergency immediately.