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SECTION - A

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Q1.1 — Parkinson's Disease (72-year-old male, DaTscan confirmed)

(a) Pharmacotherapy (5 marks)

• Levodopa is the dopamine precursor that crosses the blood-brain barrier (BBB). Carbidopa is a peripheral dopa decarboxylase inhibitor that prevents peripheral conversion, increasing CNS availability and reducing peripheral side effects.
• Dose: Start low, titrate upward.
• Most effective for bradykinesia and rigidity.

• Pramipexole, Ropinirole (non-ergot, preferred)
• Bromocriptine, Cabergoline (ergot alkaloids - less used)
• Act directly on D2/D3 receptors; useful to reduce levodopa dose and "wearing-off" phenomenon.

• Selegiline, Rasagiline
• Inhibit MAO-B, preventing dopamine breakdown in the CNS.

• Entacapone, Tolcapone
• Inhibit catechol-O-methyl transferase, prolonging levodopa effect and reducing "off" periods.

• Benztropine, Trihexyphenidyl (Procyclidine)
• Reduce cholinergic overactivity. Particularly effective for tremor; less effective for akinesia.

• Antiviral with anti-PD properties. Mechanism: increases dopamine release, blocks NMDA receptors.
• Useful for mild symptoms and levodopa-induced dyskinesias.

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(b) Adverse Drug Effects of PD drugs (3 marks)

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(c) Minimizing Adverse Drug Reactions (2 marks)

1. Always combine Levodopa with Carbidopa - reduces peripheral side effects (nausea, vomiting, cardiac arrhythmias) by 80%.
2. Take levodopa with food to reduce nausea (but high-protein meals reduce absorption - counsel patients).
3. Start with low dose and titrate slowly ("start low, go slow" principle).
4. Add Domperidone (peripheral dopamine antagonist) for nausea - does NOT cross BBB, so doesn't worsen PD.
5. Avoid abrupt withdrawal - risk of Neuroleptic Malignant Syndrome (NMS)-like reaction.
6. Drug holidays under supervision may help reduce dyskinesias.
7. Avoid anticholinergics in elderly due to cognitive impairment risk.
8. Monitor liver function when using Tolcapone (hepatotoxic).

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Q1.2 — Gout (58-year-old male, elevated uric acid, tophi)

(a) Drug Therapy for Long-term Management (5 marks)

• Mechanism: Xanthine oxidase inhibitor (XOI); blocks conversion of hypoxanthine/xanthine to uric acid.
• Dose: Start 100 mg/day, increase to 300-600 mg/day to achieve target serum uric acid < 6 mg/dL (< 5 mg/dL in tophaceous gout).
• Most cost-effective, widely used.

• Mechanism: Non-purine selective xanthine oxidase inhibitor.
• Advantage over allopurinol: can be used in mild-moderate renal impairment without dose adjustment.
• Dose: 40-80 mg/day.

• Mechanism: Inhibits renal tubular reabsorption of urate (URAT1 transporter).
• Used when allopurinol is contraindicated or intolerable.
• Avoid in renal stones, renal failure.

• Uricosuric agent; more potent; used when other drugs fail.

• Low-dose Colchicine (0.5-1 mg/day) for 3-6 months when starting ULT - prevents mobilization flares.
• Alternative: Low-dose NSAIDs or low-dose prednisolone.

• Recombinant uricase - converts uric acid to allantoin (more soluble, easily excreted).
• IV infusion every 2 weeks.

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(b) Adverse Effects of Commonly Prescribed Drugs (3 marks)

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(c) Drug Names for Acute Gout (2 marks)

1. Colchicine - 0.5-1.2 mg loading, then 0.5-0.6 mg every 1-2 h until pain relief (mechanism: inhibits tubulin polymerization, prevents neutrophil migration)
2. NSAIDs - Indomethacin (drug of choice for acute gout - 50 mg TDS), Naproxen, Diclofenac
3. Corticosteroids - Oral prednisolone or intra-articular methylprednisolone (when NSAIDs/colchicine contraindicated)
4. IL-1 inhibitors - Canakinumab, Anakinra (for refractory acute attacks)

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Q1.3 — Bronchial Asthma (Moderate) — Classification, MOA, Adverse Effects (10 marks)

Classification of Drugs for Moderate Bronchial Asthma (3 marks)

1. Beta-2 Agonists (SABAs): Salbutamol (Albuterol), Terbutaline - short-acting, for acute relief
2. Beta-2 Agonists (LABAs): Salmeterol, Formoterol - long-acting, controller therapy (always with ICS)
3. Anticholinergics: Ipratropium (SAMA), Tiotropium (LAMA) - block bronchoconstriction
4. Methylxanthines: Theophylline - oral controller

1. Inhaled Corticosteroids (ICS): Beclomethasone, Budesonide, Fluticasone - cornerstone of moderate asthma
2. Leukotriene Receptor Antagonists (LTRAs): Montelukast, Zafirlukast
3. Mast Cell Stabilizers: Sodium cromoglicate, Nedocromil (prophylactic only)

• Omalizumab (anti-IgE), Mepolizumab (anti-IL-5)

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Mechanism of Action (5 marks)

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Common Adverse Effects (2 marks)

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SECTION - B (Q-2: Short Answer - Any Three out of Four)

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Q2.1 — Drugs for Prophylaxis of Migraine (5 marks)

1. Beta-blockers: Propranolol (most evidence), Metoprolol, Timolol
   • Mechanism: Reduce cortical spreading depression, inhibit serotonergic neurons in raphe nuclei.
2. Tricyclic Antidepressants (TCAs): Amitriptyline (10-75 mg at night)
   • Mechanism: Block serotonin/norepinephrine reuptake; sodium channel stabilization.
3. Valproate/Divalproex: 500-1500 mg/day
   • Mechanism: GABA enhancement, voltage-gated sodium channel blockade.
4. Topiramate: 25-100 mg/day
   • Mechanism: Blocks Na+ channels, enhances GABA, inhibits glutamate.

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Q2.2 — Plasma Protein Binding: Clinical Significance (5 marks)

1. Volume of Distribution (Vd): Highly protein-bound drugs have low Vd (confined to plasma); low-protein-bound drugs have high Vd.
2. Drug interactions - displacement:
   • When drug A displaces drug B from albumin binding site, free drug B increases suddenly → toxicity.
   • Example: Warfarin + Aspirin/Sulfonamides → warfarin displaced → bleeding risk.
   • Phenytoin displaced by Valproate → phenytoin toxicity.
3. Drug distribution:
   • Albumin (52-68 g/L in plasma) binds acidic drugs (phenytoin, warfarin, NSAIDs, penicillin).
   • Alpha-1 acid glycoprotein (AAG) binds basic drugs (propranolol, lidocaine, tricyclics).
4. Disease states alter protein binding:
   • Hypoalbuminemia (cirrhosis, nephrotic syndrome, malnutrition) → increased free drug → toxicity risk (e.g., phenytoin, warfarin).
   • Uremia → displacement of drugs by accumulated organic acids.
   • Pregnancy → dilutional hypoalbuminemia.
5. Drug monitoring: For highly protein-bound drugs, total plasma levels may be misleading. Free-drug levels are more meaningful (e.g., free phenytoin in hypoalbuminemia).
6. First-pass extraction: High extraction drugs (propranolol, lidocaine) - protein binding limits hepatic extraction; changes in binding alter hepatic clearance.

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Q2.3 — Drug Therapy of Organophosphate Poisoning (5 marks)

• Muscarinic: Salivation, Lacrimation, Urination, Defecation, GI cramps, Emesis; bradycardia, bronchoconstriction, miosis
• Nicotinic: Muscle fasciculations, weakness, paralysis
• CNS: Anxiety, seizures, coma

• Dose: 2-4 mg IV every 5-10 min until secretions dry up (drying of bronchial secretions = endpoint, NOT pupil size)
• High doses may be required in severe poisoning (50-100+ mg in 24 hours)
• Mechanism: Competitive antagonist at muscarinic receptors; does NOT reverse nicotinic/CNS effects.

• Dose: 1-2 g IV over 15-30 min, then infusion (300-400 mg/h)
• Mechanism: Reactivates inhibited AChE by displacing the OP from the serine active site ("aging" must not have occurred - hence must be given early, within 24-48 hours)
• Reverses nicotinic (muscle) and CNS effects as well.
• MUST be given early before "aging" (irreversible covalent bond formation).

• For seizure control - 5-10 mg IV.

• Airway protection, oxygen, assisted ventilation
• Remove contaminated clothing, wash skin
• Activated charcoal if oral ingestion within 1 hour
• Gastric lavage

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Q2.4 — Opioid Analgesics: Classification + Morphine vs Pethidine (5 marks)

Classification of Opioid Analgesics (2 marks)

1. Pure agonists: Morphine, Codeine, Pethidine (Meperidine), Fentanyl, Methadone, Tramadol, Oxycodone
2. Partial agonists: Buprenorphine (mu-partial agonist)
3. Mixed agonist-antagonists: Pentazocine (kappa agonist, mu antagonist), Nalbuphine, Butorphanol
4. Antagonists: Naloxone, Naltrexone

• Short-acting: Morphine, Pethidine, Fentanyl
• Long-acting: Methadone, slow-release morphine

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Differences Between Morphine and Pethidine (3 marks)

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SECTION - B (Q-3: Case-Based - Any Three out of Four)

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Q3.1 — Case: 20-year-old Female, Status Epilepticus, Stopped Medication

(a) Condition and Drug She Was Taking (2 marks)

• Hirsutism + hoarseness are side effects of Valproic Acid/Sodium Valproate (weight gain, alopecia, polycystic ovarian syndrome-like effects in women, hirsutism). However, gingival hyperplasia, coarsening of features, and hirsutism are classic Phenytoin effects.
• Given the combination of facial hair growth and hoarseness: most likely Phenytoin (hirsutism is a well-known side effect) or Valproate (PCOS features in women).
• Most likely answer: Phenytoin - known for hirsutism, coarsening of facial features.

(b) Pharmacotherapy of Status Epilepticus (3 marks)

• Airway, Breathing, Circulation (ABC)
• IV access, oxygen, glucose check
• Draw blood for electrolytes, anticonvulsant levels

• IV Lorazepam 0.1 mg/kg IV (max 4 mg) - drug of choice; repeat once after 5-10 min
• OR IV Diazepam 0.15-0.2 mg/kg (max 10 mg IV) - can be given PR if no IV access
• OR IM Midazolam 10 mg IM (equally effective, faster in out-of-hospital setting)
• Mechanism: Enhance GABA-A receptor function → CNS depression and seizure termination.

• IV Valproate 40 mg/kg at 6 mg/kg/min (max 3000 mg) - preferred
• OR IV Fosphenytoin 20 mg PE/kg at 150 mg/min (prodrug of phenytoin, safer)
• OR IV Phenytoin 20 mg/kg at 50 mg/min (in NS, not dextrose - will precipitate)
• OR IV Levetiracetam 60 mg/kg (max 4500 mg) - gaining preference

• General anesthesia/ICU: IV Midazolam infusion, Propofol infusion, Pentobarbital/Thiopental infusion
• Continuous EEG monitoring required.

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Q3.2 — Case: 45-year-old Male, Fluctuating Muscle Weakness, Ptosis, Worse in Evening

(a) Condition and Confirmatory Test (2 marks)

• Ptosis (drooping eyelid)
• Diplopia (extraocular muscle involvement)
• Fatigable weakness - worse at end of day/evening (characteristic of MG)
• Proximal muscle weakness (shoulders, hands)

1. Edrophonium (Tensilon) Test - IV edrophonium (short-acting AChE inhibitor) → transient dramatic improvement in weakness within 30 seconds = positive. (Classic diagnostic test)
2. Anti-AChR antibodies (anti-acetylcholine receptor antibodies) - present in 85-90% of generalized MG - most specific.
3. Anti-MuSK antibodies - positive in seronegative MG.
4. Repetitive nerve stimulation (RNS) - shows decremental response at 3 Hz.
5. Single-fiber EMG - most sensitive.
6. CT chest - for thymoma (associated in 10-15%).

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(b) Drugs Used in Treatment (3 marks)

• Pyridostigmine (Mestinon) - oral 30-60 mg every 4-6 hours; most commonly used
• Neostigmine - oral or IV/IM; used in acute settings and myasthenic crisis
• Mechanism: Reversibly inhibit AChE → ACh accumulates at NMJ → improved neuromuscular transmission.
• SE: Muscarinic side effects (excess secretions, diarrhea, bradycardia, sweating) - treat with Glycopyrrolate or Atropine.

• Prednisolone (corticosteroids) - first-line immunosuppressant; 1 mg/kg/day; may cause initial worsening.
• Azathioprine - steroid-sparing agent; onset delayed 6-12 months; useful for maintenance.
• Mycophenolate mofetil - alternative to azathioprine.
• Cyclosporine, Tacrolimus - for refractory cases.
• Rituximab - anti-CD20 antibody; for refractory, especially anti-MuSK positive.

• Plasmapheresis - removes anti-AChR antibodies; rapid onset (days).
• IV Immunoglobulin (IVIg) - 2 g/kg over 2-5 days; modulates immune response.

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Q3.3 — Case: 60-year-old Male, Stable Angina, Relieved by Sublingual NTG

(a) Condition and Drug of Choice (2 marks)

• Substernal chest tightness on exertion (walking, climbing stairs, emotional stress)
• Relieved by rest or sublingual nitroglycerin within 3-5 minutes
• Consistent pattern (frequency, duration unchanged over 3 months)

• For immediate/acute relief: Sublingual Nitroglycerin (GTN - Glyceryl Trinitrate) 0.3-0.6 mg SL
• For long-term prophylaxis (first-line): Beta-blocker (e.g., Atenolol, Metoprolol) - reduces anginal frequency, improves exercise tolerance, prevents MI.
• If beta-blockers contraindicated: Calcium channel blockers (Amlodipine, Diltiazem).

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(b) Uses and Adverse Drug Reactions of Nitrates (3 marks)

1. Acute relief of angina - Sublingual GTN (0.3-0.6 mg) or GTN spray; onset 1-2 minutes
2. Prophylaxis of angina - Oral isosorbide mononitrate (ISMN) or isosorbide dinitrate (ISDN); transdermal GTN patch
3. Unstable angina - IV nitroglycerin (continuous infusion)
4. Acute left ventricular failure/pulmonary edema - IV GTN; reduces preload and afterload
5. Acute MI (in absence of hypotension, RV infarct) - IV NTG
6. Hypertensive urgency - IV nitroglycerin (sodium nitroprusside preferred)
7. Esophageal spasm - SL GTN relieves smooth muscle spasm
8. Anal fissures - GTN 0.2-0.4% topical ointment (relaxes internal anal sphincter)
9. Cyanide antidote - Sodium nitrite (component of cyanide antidote kit)

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Q4 — Skeletal Muscle Relaxants (2+3 = 5 marks)

Classification of Skeletal Muscle Relaxant Drugs (2 marks)

1. Non-depolarizing (competitive) blockers:
   • Short-acting: Mivacurium
   • Intermediate-acting: Atracurium, Cisatracurium, Vecuronium, Rocuronium
   • Long-acting: Pancuronium, Tubocurarine (d-TC)
   • Mechanism: Competitive antagonists at nicotinic (Nm) receptors at NMJ. Reversed by neostigmine.
2. Depolarizing blockers:
   • Succinylcholine (Suxamethonium) - only one in use
   • Mechanism: Persistent depolarization of end-plate (Phase 1 block → Phase 2 block); not reversed by neostigmine.

1. Acting on spinal cord:
   • Baclofen - GABA-B agonist
   • Tizanidine - alpha-2 agonist
   • Mephenesin (prototype), Methocarbamol, Chlorzoxazone, Metaxalone
2. Acting on supraspinal centers:
   • Diazepam (benzodiazepine) - enhances GABA-A
3. Direct acting on muscle:
   • Dantrolene - blocks ryanodine receptor → prevents calcium release from SR (NOT centrally acting but included in SMR group)

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Uses of Centrally Acting Skeletal Muscle Relaxants (3 marks)

1. Spasticity:
   • Baclofen: First-line for spasticity in multiple sclerosis, spinal cord injuries; intrathecal pump for severe spasticity.
   • Tizanidine: Spasticity in MS, ALS, stroke; also used in neck/back spasm.
   • Diazepam: Spasm due to upper motor neuron lesions.
2. Acute musculoskeletal spasm (muscle pain syndromes):
   • Methocarbamol, Chlorzoxazone, Cyclobenzaprine - for acute back pain, neck pain, torticollis, sprains.
   • Often combined with analgesics (paracetamol + chlorzoxazone = Parafon forte).
3. Tetanus:
   • Diazepam (IV/intrathecal) - first-line for spasms in tetanus.
   • Baclofen (intrathecal) - for severe/refractory tetanus spasms.
4. Malignant hyperthermia:
   • Dantrolene (direct-acting; blocks ryanodine receptor) - drug of choice for malignant hyperthermia triggered by succinylcholine/halothane.
5. Neuroleptic malignant syndrome (NMS):
   • Dantrolene + Bromocriptine.
6. Stiff-man syndrome:
   • Diazepam, Baclofen.

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SECTION - B (Q-4: Short Answer Questions - Any Four out of Five)

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Q4.1 — Pharmacotherapy of Open Angle Glaucoma (5 marks)

• Latanoprost (0.005%), Bimatoprost (0.03%), Travoprost
• Mechanism: Increase uveoscleral outflow of aqueous humor (FP receptor agonists)
• Use: Once daily (nighttime); reduces IOP by 25-33%
• SE: Iris pigmentation (browning), eyelash growth (hypertrichosis), conjunctival hyperemia, periorbital fat atrophy

• Timolol (0.25%, 0.5%) - non-selective; most widely used
• Betaxolol - cardioselective (safer in asthma)
• Mechanism: Reduce aqueous humor production by blocking beta-receptors in ciliary body epithelium
• SE: Bradycardia, bronchospasm (timolol; avoid in asthma), systemic absorption, depression, impotence

• Brimonidine (0.1-0.2%), Apraclonidine
• Mechanism: Reduce aqueous production + increase uveoscleral outflow
• SE: Allergic conjunctivitis, dry mouth, drowsiness, apnea in infants

• Topical: Dorzolamide (2%), Brinzolamide (1%)
• Systemic: Acetazolamide (500 mg/day) - for acute glaucoma attacks
• Mechanism: Inhibit carbonic anhydrase in ciliary body → reduce HCO3- production → reduce aqueous humor production
• SE (systemic): Metabolic acidosis, hypokalemia, paresthesias, renal stones, sulfonamide allergy

• Pilocarpine 1-4% (muscarinic agonist)
• Mechanism: Contracts ciliary muscle and sphincter pupillae → opens trabecular meshwork → increases outflow
• SE: Miosis, browache, accommodative spasm; rarely - retinal detachment
• Currently used mainly in acute angle-closure glaucoma or as add-on

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Q4.2 — Phases of Clinical Trial (5 marks)

• Phase I: First-in-human; uses single ascending dose (SAD) and multiple ascending dose (MAD) designs.
• Phase II: Proof of concept; often dose-finding (Phase IIa) and efficacy (Phase IIb).
• Phase III: Double-blind, randomized controlled trial; mandatory for regulatory approval (CDSCO in India, FDA in USA, EMA in EU).
• Phase IV: Can lead to drug withdrawal if serious ADRs detected (e.g., Rofecoxib withdrawn due to cardiac events).

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Q4.3 — Cardioselective Beta-blockers: List, Uses, Adverse Effects (5 marks)

1. Metoprolol
2. Atenolol
3. Bisoprolol
4. Acebutolol (has intrinsic sympathomimetic activity - ISA)
5. Betaxolol (ophthalmic use)
6. Esmolol (ultra-short IV)
7. Nebivolol (also releases NO - vasodilatory)
8. Celiprolol

1. Hypertension - reduce cardiac output; inhibit renin release
2. Ischemic heart disease - stable and unstable angina; reduce myocardial oxygen demand by reducing HR and contractility
3. Post-MI (secondary prevention) - reduce mortality by 20-25%; started early
4. Heart failure (chronic) - Carvedilol, Metoprolol, Bisoprolol (reduce morbidity and mortality in stable HFrEF)
5. Arrhythmias - SVT, atrial fibrillation (rate control), ventricular tachycardia
6. Hyperthyroidism - control sympathomimetic symptoms (tachycardia, tremor, anxiety)
7. Migraine prophylaxis - Propranolol, Metoprolol
8. Portal hypertension - Propranolol (reduces portal pressure)
9. Glaucoma - Timolol, Betaxolol (topical)
10. Anxiety/performance anxiety, essential tremor - Propranolol

• Safer in asthma and COPD (less beta-2 blockade → less bronchospasm)
• Less interference with hypoglycemia response in diabetics
• Less peripheral vasoconstriction (less Raynaud's exacerbation)

1. Bradycardia and heart block - due to beta-1 blockade; contraindicated in pre-existing AV block
2. Bronchospasm - even cardioselective agents can cause at high doses; avoid in asthma
3. Cold extremities and Raynaud's phenomenon - beta-2 mediated vasodilation blocked
4. Fatigue, lethargy, depression - CNS effects
5. Masking hypoglycemia symptoms - blunts tachycardia (warning sign); sweating still occurs
6. Rebound phenomenon - abrupt withdrawal → tachycardia, hypertension, angina; taper over 1-2 weeks
7. Hyperlipidemia - increase TG, decrease HDL (especially non-selective)
8. Sexual dysfunction (impotence)
9. Hyperkalemia (block beta-2 mediated K+ uptake)
10. Worsening heart failure acutely (negative inotropic) - use with caution in decompensated HF

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Q4.4 — Local Anaesthetics (5 marks)

• Block voltage-gated sodium channels (VGSCs) → prevent Na+ influx → depolarization fails → action potential not propagated → conduction block.
• Preferentially bind to the open (activated) or inactivated state of Na+ channels (use-dependent or frequency-dependent block).
• Small-diameter fibers (pain, temperature: C and A-delta) blocked before large fibers (motor).
• Order of blockade: Autonomic (B fibers) → Pain, Temp → Touch, Pressure → Motor.

• Structure: Aromatic lipophilic group - Intermediate chain (ester or amide) - Ionizable amino group.
• Esters: Procaine (prototype), Cocaine (only LA that also causes vasoconstriction), Benzocaine, Tetracaine, Chloroprocaine
  • Metabolized by plasma pseudocholinesterase
  • More allergenic (PABA metabolite)
• Amides: Lignocaine/Lidocaine (most used), Bupivacaine, Ropivacaine, Levobupivacaine, Prilocaine, Mepivacaine
  • Metabolized in liver
  • Less allergenic, more stable

• pKa: Lower pKa → more un-ionized at physiologic pH → faster onset (lipid-soluble form penetrates membrane)
• In acidic tissues (infected/inflamed): more ionized form → poor efficacy (e.g., dental infection)
• Adding epinephrine (1:200,000): causes vasoconstriction → reduces systemic absorption → prolongs duration → reduces bleeding. AVOID in finger, toe, penis, nose, ear (end arteries → ischemia/gangrene).

• Short-acting: Procaine (60-90 min)
• Intermediate: Lidocaine (1.5-2 h), Mepivacaine
• Long-acting: Bupivacaine (3-10 h), Ropivacaine, Tetracaine

1. Topical (surface) anesthesia - Lignocaine gel, EMLA cream (lignocaine + prilocaine)
2. Infiltration anesthesia - injected into tissues
3. Peripheral nerve block - femoral, brachial plexus
4. Epidural (extradural) block
5. Spinal (subarachnoid) block - bupivacaine, lignocaine
6. IV regional anesthesia (Bier's block) - lignocaine
7. Intravenous use - Lidocaine for ventricular arrhythmias

• CNS: Initially stimulation (restlessness, tremors, seizures) then depression; dose-dependent.
• CVS: Hypotension, arrhythmias, cardiac arrest; Bupivacaine cardiotoxic (blocks Na+ channels in heart, difficult to resuscitate; use ropivacaine/levobupivacaine as safer alternatives).
• Methemoglobinemia: Prilocaine (o-toluidine metabolite), Benzocaine.
• Allergy: Esters > Amides; PABA is the antigenic metabolite of ester LAs.

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Q4.5 — Pharmacotherapy of Status Asthmaticus (5 marks)

1. Oxygen - high-flow oxygen to maintain SpO2 94-98%
2. Short-acting beta-2 agonists (SABAs) - Salbutamol 2.5-5 mg nebulized every 20 min for 3 doses, then as needed; or MDI 4-8 puffs via spacer.
3. Ipratropium bromide (anticholinergic) - 0.5 mg nebulized q20 min × 3, then q2-4 h; additive bronchodilation with SABA.
4. Systemic corticosteroids - IV Hydrocortisone 200 mg stat then 100 mg q4h, or oral Prednisolone 40-50 mg/day × 5-7 days (equally effective if tolerated orally); onset of action 4-6 hours; KEY anti-inflammatory drug.

• Morphine (causes histamine release → worsens bronchospasm)
• Non-selective beta-blockers (cause bronchoconstriction)
• NSAIDs (aspirin-exacerbated respiratory disease)
• Sedatives (except if intubating)

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SECTION - C (Q-5: Short Answer - Choice within each question)

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Q5.1 — Factors Affecting Bioavailability (5 marks)

Factors Affecting Oral Bioavailability:

1. Lipid solubility: Lipophilic drugs absorbed better; hydrophilic drugs poorly absorbed.
2. Molecular size: Large molecules poorly absorbed (e.g., heparin, insulin - not orally bioavailable).
3. Ionization: Un-ionized drugs absorbed better. pKa and gastric/intestinal pH determine ionization (Henderson-Hasselbalch).
4. Particle size and crystal form: Smaller particle size → better dissolution → better absorption (micronization of griseofulvin).

1. Disintegration and dissolution: Rate-limiting step for many solid oral dosage forms.
2. Excipients: Fillers, binders, coatings affect dissolution.
3. Enteric coating delays absorption.
4. Modified-release formulations alter absorption rate.

1. Gastric emptying rate: Faster emptying → faster delivery to small intestine (main absorption site) → faster absorption. Food slows gastric emptying.
2. Gut motility: Increased motility (diarrhea) reduces absorption time. Reduced motility (constipation) may increase absorption.
3. GI pH:
   • Acidic stomach pH → protonation of basic drugs → ionized → reduced absorption
   • Antacids, PPIs raise gastric pH → alter ionization and absorption
4. Splanchnic blood flow: Reduced flow (shock) reduces absorption.
5. Mucosal integrity: Malabsorption syndromes (celiac, Crohn's) reduce absorption.
6. Efflux transporters: P-glycoprotein (P-gp) in gut wall pumps drugs back into lumen → reduces F (e.g., digoxin, many HIV drugs).

• Most important factor for orally administered drugs.
• Drug absorbed from gut → portal circulation → liver before reaching systemic circulation.
• High hepatic extraction drugs have low F due to extensive first-pass: Morphine (F=25%), Propranolol (F=30%), Nitroglycerin (F=<1%), Lignocaine (F<40%), Verapamil, Metoprolol.
• Gut wall metabolism: CYP3A4 in enterocytes also contributes (e.g., cyclosporine).
• Avoid first-pass: Sublingual (GTN), transdermal, rectal (partial), IV routes bypass liver.

1. Enzyme induction (rifampicin, carbamazepine) → increased first-pass → reduced F.
2. Enzyme inhibition (ketoconazole, erythromycin) → increased F → potential toxicity.
3. Chelation: Tetracycline + Ca2+/Mg2+/Fe2+ → insoluble complex → reduced absorption.
4. Antacids → complex with many drugs → reduced absorption.

• Food may reduce (tetracycline, ampicillin, rifampicin), delay (aspirin), or increase (griseofulvin with fatty food, itraconazole) bioavailability.

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Q5.1 (OR) — Therapeutic Uses and Adverse Effects of Morphine (5 marks)

Therapeutic Uses:

1. Severe pain management:
   • Post-operative pain (IM/IV)
   • Cancer pain (oral modified-release morphine - first-line in WHO analgesic ladder step 3)
   • Trauma, burns, renal colic (IV/IM)
   • Myocardial infarction - relieves chest pain and anxiety; reduces cardiac workload (causes venodilation → preload reduction); analgesic of choice in AMI
2. Acute pulmonary edema (APO):
   • IV morphine reduces dyspnea dramatically; decreases preload (venodilation) and anxiety; obtunds respiratory center awareness of hypoxia.
3. Diarrhea:
   • Codeine (methylmorphine) and loperamide more commonly used; morphine reduces gut motility.
4. Cough suppression:
   • Codeine (methylmorphine) - primary antitussive; morphine less preferred for cough.
5. Pre-anesthetic medication:
   • Reduces anxiety, provides basal analgesia, reduces anesthetic requirements.
6. Palliative care:
   • Chronic pain, dyspnea in terminal disease.
7. Sickle cell crisis, obstetric analgesia (with caution).

Adverse Effects:

1. Respiratory depression - most serious and potentially fatal; mu-receptor mediated depression of respiratory center; treat with naloxone.
2. Sedation, drowsiness
3. Euphoria (basis of dependence)
4. Nausea and vomiting (CTZ stimulation; worse in ambulatory patients)
5. Miosis ("pin-point pupils") - pathognomonic of opioid toxicity
6. Tolerance and physical dependence with repeated use
7. Seizures (high doses, neonate)

• Treatment: Naloxone 0.4-2 mg IV, repeat q2-3 min

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Q5.2 — Bioethics and Its Importance in Medical Practice (5 marks)

1. Autonomy (Respect for persons):
   • Every competent individual has the right to make informed decisions about their own healthcare.
   • Requires: Informed consent, truth-telling, confidentiality.
   • Example: Respecting a patient's right to refuse treatment.
2. Beneficence (Do good):
   • Obligation to act in the patient's best interest; promote health and well-being.
   • Example: Prescribing evidence-based treatment; recommending vaccination.
3. Non-maleficence (Do no harm - Primum non nocere):
   • Avoid causing unnecessary harm; weigh benefits against risks.
   • Example: Avoiding unnecessary investigations, polypharmacy, experimental treatments without evidence.
4. Justice:
   • Fair distribution of health resources and benefits; treat patients equally regardless of race, gender, economic status.
   • Example: Allocating ICU beds equitably; providing essential drugs to all patients.

1. Informed consent: Ethically and legally required before any procedure; patient must understand risks, benefits, alternatives.
2. Research ethics: Helsinki Declaration principles; IRB/Ethics Committee oversight; protecting human subjects in clinical trials (no exploitation).
3. End-of-life care: Decisions about withholding/withdrawing treatment; DNR orders; palliative care.
4. Resource allocation: Rationing of expensive drugs, organ transplant, ICU.
5. Confidentiality: Protecting patient information; exceptions (public health reporting, court orders).
6. Conflict of interest: Physicians must not be influenced by pharmaceutical companies in prescribing.
7. Professional integrity: Prevents exploitation, negligence, and misconduct.

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Q5.2 (OR) — Principles of Good Communication with Patients Regarding Drug Use for Chronic Conditions and Challenges (5 marks)

Principles of Good Communication:

1. Clarity and simplicity:
   • Use plain language, avoid medical jargon. "Take this tablet twice daily with food" instead of "take this drug bid with meals."
2. Informed consent and education:
   • Explain the purpose, expected benefits, and duration of therapy.
   • Explain what will happen if medication is NOT taken (consequences of non-adherence).
3. Medication counseling (5 R's):
   • Right drug, Right dose, Right time, Right route, Right patient.
   • Explain HOW, WHEN, and for HOW LONG to take the medication.
4. Addressing adverse effects honestly:
   • Warn about common side effects; reassure that many are transient.
   • Tell patient when to seek help (e.g., rash, jaundice, severe bleeding).
5. Motivational interviewing / shared decision making:
   • Involve the patient in treatment decisions; understand their concerns and preferences.
   • Explore reasons for non-adherence (cost, fear of side effects, cultural beliefs).
6. Teach-back method:
   • Ask patient to repeat instructions back to verify understanding.
7. Written instructions:
   • Provide prescription with clear written instructions, especially for elderly, polypharmacy, or illiterate patients.
8. Empathy and non-judgmental attitude:
   • Don't criticize patients who miss doses; understand the burden of chronic disease.
9. Regular follow-up:
   • Schedule follow-up to monitor response, adjust doses, and reinforce adherence.

Challenges in Communication:

1. Low health literacy: Many patients cannot understand medical instructions.
2. Language barriers: Dialect differences; need for interpreters.
3. Cultural and religious beliefs: May conflict with treatment (e.g., refusal of blood products).
4. Complexity of regimen: Multiple drugs, multiple doses → pill fatigue → poor adherence.
5. Cost of medication: Financial barriers lead to self-discontinuation.
6. Asymptomatic conditions (hypertension, hyperlipidemia): Patient may not feel ill → "Why take medicine if I feel fine?" → poor adherence.
7. Fear of side effects: Leads to non-adherence (as in our epilepsy case - stopped due to hirsutism).
8. Time constraints in clinical practice: Physicians under time pressure → rushed consultations → poor communication.
9. Misinformation: Social media, family, and alternative medicine providers giving incorrect advice.
10. Elderly patients: Cognitive decline, polypharmacy, poor manual dexterity (inhalers, patches).

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SECTION - A

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Q1.1 — UTI (32-year-old woman, E. coli, pyuria)

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(a) Classification of Drugs Used in UTI Treatment (3 marks)

• Norfloxacin, Ciprofloxacin, Ofloxacin, Levofloxacin

• Co-trimoxazole (Trimethoprim + Sulfamethoxazole; TMP-SMX)
• Trimethoprim alone

• Nitrofurantoin (drug of choice for uncomplicated cystitis, especially in pregnancy)
• Nitrofurazones

• Amoxicillin, Amoxicillin-clavulanate
• Cephalexin, Cefuroxime, Cefixime

• Fosfomycin trometamol - single-dose oral therapy for uncomplicated UTI

• Gentamicin, Amikacin

• Imipenem, Meropenem

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(b) Pharmacological Basis of Drugs Used (5 marks)

• Mechanism: Inhibit bacterial DNA gyrase (topoisomerase II) and topoisomerase IV.
  • DNA gyrase: introduces negative supercoils → relieves torsional stress ahead of replication fork.
  • Topoisomerase IV: decatenates daughter DNA strands after replication.
  • Fluoroquinolones stabilize the drug-enzyme-DNA "cleavable complex" → double-strand DNA breaks → bacterial cell death.
• Spectrum: Broad-spectrum; active against gram-negative rods (E. coli, Klebsiella, Pseudomonas), Staphylococcus (ciprofloxacin less for MRSA).
• Norfloxacin is primarily concentrated in urine/GI tract; used specifically for UTI and GI infections.
• Bactericidal; concentration-dependent killing.

• Mechanism: Sequential blockade of folate synthesis pathway - "double block."
  • Sulfamethoxazole: Structural analogue of PABA (para-aminobenzoic acid) → competitive inhibition of dihydropteroate synthase → blocks conversion of PABA to dihydropteroic acid (step 1).
  • Trimethoprim: Inhibits bacterial dihydrofolate reductase (DHFR) → prevents reduction of dihydrofolate to tetrahydrofolate (active form) (step 2).
  • Combined effect: synergistic bactericidal action; neither drug alone is fully bactericidal at these doses.
• Pharmacokinetics: TMP:SMX ratio 1:5 by weight; both drugs achieve similar plasma levels; both excreted in urine (hence effective for UTI).

• Mechanism: Prodrug activated by bacterial nitrofuran reductase → reactive intermediates (nitroso radical anions) → damage bacterial DNA, inhibit ribosomal proteins and pyruvate dehydrogenase → bactericidal.
• Concentrated in urine (60-70% excreted unchanged in urine) → high urinary drug levels.
• Active against E. coli, Staphylococcus saprophyticus, Enterococcus; NOT active against Pseudomonas, Proteus, Klebsiella.
• Advantage: Minimal systemic absorption → less impact on normal flora, lower resistance.

• Mechanism: Bind to Penicillin-Binding Proteins (PBPs - transpeptidases, carboxypeptidases) → inhibit cross-linking of peptidoglycan chains → weakened cell wall → osmotic lysis → bactericidal.
• Beta-lactamase inhibitor (clavulanic acid) blocks beta-lactamase enzyme that breaks the beta-lactam ring → restores activity against resistant organisms.

• Mechanism: Inhibits MurA (phosphoenolpyruvate transferase) → blocks synthesis of UDP-N-acetylmuramic acid (first step in peptidoglycan synthesis) → bactericidal.
• Single-dose (3 g sachet) effective for uncomplicated cystitis in women.

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(c) Drugs for Long-term Prophylaxis of Recurrent UTI (2 marks)

1. Nitrofurantoin 50-100 mg at bedtime (preferred; well tolerated)
2. Trimethoprim 100 mg at bedtime
3. Co-trimoxazole 1 single-strength tablet (480 mg) at bedtime or 3 times/week
4. Norfloxacin 200 mg at bedtime (if above fail)
5. Cephalexin 125-250 mg at bedtime (safe in pregnancy)
6. Fosfomycin 3 g sachet every 10 days

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Q1.2 — Peptic Ulcer Disease: Classification, Pharmacotherapy, Adverse Effects (10 marks)

(a) Classification of Drugs Used in Peptic Ulcer (3 marks)

1. Proton Pump Inhibitors (PPIs):
   • Omeprazole, Pantoprazole, Rabeprazole, Lansoprazole, Esomeprazole
2. H2-Receptor Antagonists (H2RAs):
   • Ranitidine, Famotidine, Cimetidine, Nizatidine
3. Anticholinergics:
   • Pirenzepine (M1 selective) - rarely used now
4. Prostaglandin analogues:
   • Misoprostol (PGE1 analogue) - reduces acid, increases mucus

• Aluminium hydroxide, Magnesium hydroxide (Magaldrate), Sodium bicarbonate, Calcium carbonate
• Combination: Maalox, Gelusil

1. Sucralfate - aluminium salt of sucrose octasulfate
2. Bismuth compounds - Colloidal Bismuth Subcitrate (CBS), Bismuth subsalicylate
3. Misoprostol - also listed here (dual action)
4. Carbenoxolone (liquorice derivative; less used)

• Clarithromycin, Amoxicillin, Metronidazole, Tetracycline (combined with PPI/bismuth)

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(b) Pharmacotherapy of Peptic Ulcer (5 marks)

• Urea breath test, stool antigen test, rapid urease test (RUT) on endoscopic biopsy.

• PPI (e.g., Omeprazole 20 mg BD) + Clarithromycin 500 mg BD + Amoxicillin 1 g BD

• PPI BD + Bismuth subcitrate 120 mg QID + Tetracycline 500 mg QID + Metronidazole 500 mg TDS × 10-14 days

• First 5 days: PPI + Amoxicillin
• Next 5 days: PPI + Clarithromycin + Tinidazole

• Withdraw NSAID if possible.
• PPIs are the drug of choice - omeprazole 20 mg OD (or 40 mg if severe), 4-8 weeks for duodenal ulcer, 8-12 weeks for gastric ulcer.
• H2RAs - ranitidine 150 mg BD (second-line; less potent than PPIs).
• Misoprostol - for NSAID-induced ulcer prevention (200 mcg QID with food).
• Sucralfate - 1 g QID 30 min before meals; adjuvant cytoprotection.

• PPIs: Irreversibly inhibit H+/K+-ATPase (proton pump) of parietal cells → most potent acid suppressors. Are prodrugs (activated by acid in canalicular space to sulphenamide that binds cysteine residues of pump). Activate only after a meal (pump active when patient has eaten). Omeprazole reduces basal + stimulated acid secretion by >95%.
• H2RAs (Ranitidine): Competitively block histamine H2 receptors on parietal cells → reduce cAMP → reduce H+/K+-ATPase activity → reduce acid secretion. Effective for nocturnal acid secretion. Cross the placenta (category B).
• Sucralfate: In acidic pH, polymerizes and forms a viscous gel → adheres to ulcer base → physical barrier against acid/pepsin. Also binds bile salts. Stimulates prostaglandin synthesis. Does NOT neutralize acid.
• Antacids (Al/Mg hydroxide): Chemical neutralization of HCl (Al(OH)3 + HCl → AlCl3 + H2O). Also adsorb pepsin. Fast but short-acting (1-2 h).
• Bismuth: Inhibits H. pylori, coats ulcer base, stimulates prostaglandins and mucus.

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(c) Common Adverse Effects of Peptic Ulcer Drugs (2 marks)

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Q1.3 — Hyperthyroidism / Graves' Disease (32-year-old woman)

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(a) Classification of Drugs Used in Hyperthyroidism (3 marks)

1. Carbimazole (most used in India; prodrug → methimazole)
2. Methimazole (most used in USA)
3. Propylthiouracil (PTU) - preferred in thyroid storm and first trimester pregnancy

1. Lugol's iodine (potassium iodide + iodine)
2. Potassium iodide (SSKI)
3. Radioactive iodine (I-131) - definitive treatment

1. Propranolol (most commonly used; also inhibits T4→T3 conversion)
2. Atenolol, Metoprolol

1. Perchlorate
2. Thiocyanate (Used rarely; mainly for iodine-induced hyperthyroidism)

• Definitive treatment; commonly used in adults (not in children/pregnancy).

• Not a drug but classified as definitive therapy alongside I-131.

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(b) Mechanism of Action of Drugs Used (5 marks)

• Primary mechanism: Inhibit thyroid peroxidase (TPO) enzyme → block:
  • Organification: Oxidation of iodide (I-) to iodine (I2) and incorporation into tyrosyl residues of thyroglobulin (forming MIT and DIT)
  • Coupling: Condensation of MIT + DIT to form T3 (triiodothyronine) and T4 (thyroxine)
• Additional effect (PTU only): Inhibits type 1 deiodinase in peripheral tissues → blocks conversion of T4 to the more active T3 (peripheral conversion). This is why PTU is preferred in thyroid storm.
• Immunosuppressive effect: Reduce TSH-receptor antibody (TRAb) levels → reduce stimulation of thyroid → may help achieve remission.
• Carbimazole: Converted to methimazole in the body; methimazole is the active form.
• Onset: Does not deplete existing stored hormone → takes 2-4 weeks for effects (existing T3/T4 must be depleted first). Use beta-blockers for immediate symptom relief.

• Wolff-Chaikoff effect: High concentrations of iodide temporarily inhibit organification → reduce thyroid hormone synthesis (auto-regulatory mechanism).
• Jod-Basedow phenomenon: Paradoxical hyperthyroidism in iodine-deficient patients given iodine.
• Other effects: Reduce vascularity and size of thyroid gland (useful pre-operatively).
• Use: Given 10-14 days before thyroidectomy to reduce gland vascularity and bleeding.
• Limitation: Escape phenomenon (Wolff-Chaikoff escape) occurs after 2-3 weeks → hyperthyroidism returns.

• Blocks beta-adrenergic receptors → reduces sympathomimetic manifestations of hyperthyroidism: tachycardia, palpitations, tremor, sweating, anxiety.
• Additional unique effect of Propranolol: Inhibits peripheral conversion of T4 to T3 (inhibits type 1 deiodinase) → reduces active T3 levels.
• Does NOT affect the underlying disease process or thyroid hormone synthesis.
• Gives rapid symptomatic relief while antithyroid drugs take weeks to act.

• Mechanism: I-131 concentrated in thyroid follicular cells (same as stable iodine via sodium-iodide symporter, NIS) → emits beta-particles (primary action) and gamma radiation → selective ablation of thyroid follicular cells → reduce thyroid mass and hormone production.
• Beta particles have a range of only 0.5-2 mm → tissue damage is localized to thyroid.
• Permanent effect (often leads to hypothyroidism requiring lifelong T4 replacement).

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(c) Drugs Safely Used During Pregnancy (2 marks)

1. First trimester (weeks 1-12): Propylthiouracil (PTU) is preferred.
   • Methimazole is associated with teratogenicity (aplasia cutis, choanal atresia, esophageal atresia - "methimazole embryopathy") especially in the first trimester.
   • PTU does not cross the placenta as readily as methimazole (higher protein binding of PTU).
2. Second and third trimester: Carbimazole or Methimazole preferred.
   • PTU associated with rare but serious maternal hepatotoxicity (hepatic necrosis) → not recommended long-term.
   • Use the lowest effective dose of antithyroid drug.
3. Propranolol - can be used short-term for symptomatic control; long-term use in pregnancy may cause fetal bradycardia, IUGR, neonatal hypoglycemia.

• Radioactive iodine (I-131) - ABSOLUTELY CONTRAINDICATED; destroys fetal thyroid.
• Lugol's iodine (long-term) - fetal goiter, hypothyroidism.

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SECTION - A, Q-2 (Short Answer - Any Three out of Four)

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Q2.1 — Adverse Effects and Contraindications of Glucocorticoids (5 marks)

Adverse Effects (grouped by system):

1. Hyperglycemia / Steroid diabetes - reduced glucose utilization, increased gluconeogenesis; worst in diabetics
2. Cushing's syndrome (with chronic use): central obesity (buffalo hump, moon face, truncal obesity), purple striae, easy bruising
3. Dyslipidemia - hypercholesterolemia, hypertriglyceridemia
4. Negative nitrogen balance - protein catabolism → muscle wasting, thin skin, poor wound healing

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Contraindications:

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Q2.2 — Fibrinolytics (5 marks)

• All fibrinolytics → convert plasminogen → plasmin (serine protease) → cleaves fibrin, fibrinogen, Factor V, Factor VIII → thrombus dissolution.
• Plasmin is non-specific - also degrades circulating fibrinogen → "lytic state."

• Streptokinase (from Streptococcus) - forms complex with plasminogen → activates other plasminogen molecules. Antigenic (prior streptococcal infection → antibodies → allergic reactions; cannot repeat for 6 months-1 year).
• Urokinase - derived from human urine/renal cells; less antigenic; directly activates plasminogen.

• Alteplase (tPA) - recombinant tissue plasminogen activator; preferentially activates fibrin-bound plasminogen → more clot-specific; shorter half-life (5 min) → continuous infusion needed.
• Duteplase - double-chain tPA.

• Reteplase - deleted domain tPA; longer half-life; bolus dosing.
• Tenecteplase (TNK-tPA) - single IV bolus; highest fibrin specificity; longest half-life among tPA variants; preferred in acute STEMI (weight-adjusted bolus).
• Staphylokinase - fibrin-selective; derived from S. aureus.

1. Acute STEMI (within 12 hours) - when primary PCI not available; tenecteplase/streptokinase
2. Acute ischemic stroke - alteplase within 4.5 hours of symptom onset
3. Acute massive pulmonary embolism - streptokinase, alteplase (hemodynamic compromise)
4. DVT (deep vein thrombosis) - selected cases
5. Peripheral arterial occlusion - catheter-directed thrombolysis
6. Blocked central venous catheters - alteplase

1. Bleeding (most common and serious) - major bleeding including intracranial hemorrhage (ICH). ICH occurs in ~0.5-1% with STEMI thrombolysis.
2. Allergic reactions - with streptokinase (fever, chills, anaphylaxis in 1-4%)
3. Hypotension - with streptokinase (histamine release)
4. Reperfusion arrhythmias - accelerated idioventricular rhythm after coronary thrombolysis (usually benign)
5. Re-occlusion after thrombolysis if underlying stenosis not treated

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Q2.3 — 3rd Generation Cephalosporins: MOA, Adverse Effects, Therapeutic Uses (5 marks)

• Oral: Cefixime, Cefpodoxime, Cefdinir, Ceftibuten
• Parenteral: Ceftriaxone (most used), Cefotaxime, Ceftazidime (activity vs Pseudomonas), Cefoperazone

• Beta-lactam antibiotics - contain beta-lactam ring fused with dihydrothiazine ring (cepham nucleus).
• Mechanism: Bind covalently to Penicillin-Binding Proteins (PBPs - transpeptidases, carboxypeptidases, endopeptidases) on bacterial cell membrane → inhibit cross-linking of peptidoglycan chains → cell wall weakening → osmotic lysis → bactericidal.
• PBPs normally catalyze the final transpeptidation step: D-Ala-D-Ala terminus of pentapeptide side chains of peptidoglycan precursors cross-linked via pentaglycine bridge.
• Cephalosporins mimic the D-Ala-D-Ala terminus → bind irreversibly to active site of PBPs.
• Result: bacteria cannot maintain structural integrity → lysis.
• Time-dependent killing (efficacy depends on time drug levels remain above MIC).

• Extended gram-negative coverage (Enterobacteriaceae: E. coli, Klebsiella, Proteus, Enterobacter, Serratia, H. influenzae, N. meningitidis, N. gonorrhoeae).
• Better CNS penetration (cross blood-brain barrier) - used for bacterial meningitis.
• Ceftazidime and Cefoperazone also active against Pseudomonas aeruginosa.
• Some activity maintained against gram-positive organisms.

1. Hypersensitivity reactions - skin rashes, urticaria, fever; anaphylaxis rare (0.02%); 1-10% cross-reactivity with penicillin allergy (reduced with 3rd gen).
2. GI disturbances - diarrhea, nausea, vomiting; pseudomembranous colitis (C. difficile overgrowth).
3. Ceftriaxone-specific:
   • Biliary sludge/pseudolithiasis - precipitates as calcium salt in bile (especially in neonates and with prolonged use); reversible.
   • Neonatal hyperbilirubinemia - displaces bilirubin from albumin; avoid in neonates with jaundice; use Cefotaxime instead.
4. Cefoperazone-specific:
   • Disulfiram-like reaction with alcohol (contains MTT side chain → inhibits aldehyde dehydrogenase).
   • Hypoprothrombinemia (inhibits Vitamin K-dependent clotting factors).
   • Bleeding tendency.
5. Nephrotoxicity - rare with cephalosporins alone; risk increases with aminoglycosides.
6. Neurotoxicity - high doses can cause seizures (especially in renal failure).
7. Superinfection - broad-spectrum → disrupts normal flora → Candida, C. difficile.
8. Pain at injection site (IM injections).

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Q2.4 — Prokinetic Agents: MOA, Adverse Effects, Therapeutic Uses (5 marks)

Classification and Mechanism of Action:

• Mechanism: Blocks D2 receptors in gut (removes dopamine's inhibitory effect on ACh release → enhanced cholinergic activity → increased LES tone, gastric emptying, small bowel motility). Also blocks 5-HT3 receptors at high doses. Crosses BBB → central D2 blockade → antiemetic (CTZ effect).
• Uses: Gastroparesis (especially diabetic), GERD, nausea/vomiting (postoperative, chemotherapy-induced, migraine-associated).
• ADRs: Extrapyramidal reactions (EPS) - dystonia, tardive dyskinesia (chronic), akathisia, parkinsonism (due to central D2 blockade - MAJOR drawback); hyperprolactinemia (galactorrhea, amenorrhea); sedation; QT prolongation.

• Mechanism: Peripheral D2 receptor blocker - acts on the myenteric plexus and on the chemoreceptor trigger zone (CTZ - outside BBB).
• Key advantage over metoclopramide: Does NOT cross BBB → NO extrapyramidal side effects; no CNS effects.
• Uses: Gastroparesis, nausea/vomiting, GERD; widely used in India.
• ADRs: Mild hyperprolactinemia (gynecomastia), QT prolongation (cardiac arrhythmia risk - FDA black box warning); rare EPS.

• Mechanism: Stimulates 5-HT4 receptors on myenteric plexus → enhances ACh release → promotes coordinated motility throughout GI tract (esophagus, stomach, small bowel, colon).
• Also blocks 5-HT3.
• ADRs: Fatal cardiac arrhythmias (QT prolongation, Torsades de Pointes) due to hERG K+ channel blockade → WITHDRAWN from most markets.

• Selective 5-HT4 agonist + weak 5-HT3 antagonist.
• No dopamine D2 blockade → no EPS, no QT prolongation at usual doses.
• Uses: GERD, functional dyspepsia, gastroparesis. Widely used in India.

• 5-HT4 partial agonist; withdrawn due to cardiovascular risks; now restricted to IBS-C in women.

• Erythromycin (macrolide antibiotic) - at low doses (1-3 mg/kg IV) acts as motilin receptor agonist → powerful gastric prokinetic; used for diabetic gastroparesis, ICU gastric paresis, upper GI bleeding (pre-endoscopy).
• Disadvantage: Tachyphylaxis (rapid tolerance), antibiotic resistance, QT prolongation.

• Neostigmine - IV; used for Ogilvie's syndrome (acute colonic pseudo-obstruction).
• Itopride - D2 antagonist + AChE inhibitor; used for functional dyspepsia.

• Relamorelin - for gastroparesis (investigational).

Summary: Therapeutic Uses of Prokinetics:

1. Gastroparesis (diabetic, post-surgical) - Metoclopramide, Domperidone, Mosapride, IV Erythromycin
2. GERD (reflux esophagitis) - as adjunct to acid-suppressive therapy; Domperidone, Mosapride
3. Functional dyspepsia / Bloating - Domperidone, Mosapride, Itopride
4. Nausea and vomiting (postoperative, chemotherapy-induced) - Metoclopramide
5. Facilitating nasogastric/nasojejunal tube passage
6. Small bowel dysmotility - Cisapride (limited use), Erythromycin
7. Constipation-predominant IBS - Tegaserod (restricted use)
8. Pre-endoscopy gastric emptying (upper GI hemorrhage) - IV Erythromycin

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SECTION - B (Q-3: Case-Based/Short Answer - Any Three out of Four)

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Q3.1 — Diabetic Ketoacidosis (16-year-old Type 1 DM, FBS 320 mg/dL, ketonuria)

(a) Condition and Drug of Choice (2 marks)

• Regular insulin (soluble insulin) via continuous IV infusion.

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(b) Pharmacotherapy of DKA (3 marks)

• 0.9% Normal saline (isotonic) - 1L over 30-60 min initially, then 1L/hour × 2 hours, then reduce rate.
• Switch to 0.45% NaCl if Na+ normal or elevated.
• When blood glucose drops to 250 mg/dL: add 5% Dextrose to prevent hypoglycemia while insulin infusion continues to clear ketones.
• Goal: Restore intravascular volume, improve renal perfusion (enhance ketonuria).

• Regular insulin infusion: 0.1 units/kg/h IV (continuous infusion); preceded by bolus 0.1 units/kg IV (or skip bolus in children).
• Goal: Reduce blood glucose by 50-75 mg/dL/hour.
• Continue insulin infusion until anion gap normalizes and ketones cleared (NOT just until glucose normalizes - DKA resolved when bicarbonate corrected and anion gap closed).
• When eating and DKA resolved: transition to subcutaneous insulin.
• Subcutaneous long-acting insulin (e.g., Glargine) should be started before stopping IV infusion (1-2 hour overlap) to prevent rebound DKA.

• In DKA: total body K+ depleted (lost in urine due to osmotic diuresis and vomiting), but serum K+ may be normal or HIGH initially (insulin deficiency shifts K+ out of cells).
• Start K+ replacement when serum K+ <5.5 mEq/L and urine output established.
• If K+ <3.5 mEq/L: Give KCl 40 mEq/h before starting insulin (insulin drives K+ into cells → fatal hypokalemia if not replaced first).
• Target: Serum K+ 4-5 mEq/L.

• Only if severe acidosis (pH <6.9) OR life-threatening hyperkalemia.
• NaHCO3 50-100 mEq IV over 30-60 min. Routine use not recommended (may worsen cerebral edema, paradoxical CSF acidosis, hypokalemia).

• Only if serum phosphate <1 mg/dL or respiratory/cardiac compromise due to hypophosphatemia.

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Q3.2 — Iron Parenteral Therapy in Detail (5 marks)

1. Malabsorption (celiac disease, inflammatory bowel disease, post-gastrectomy)
2. Intolerance to oral iron (severe GI side effects)
3. Non-compliance with oral iron
4. Chronic kidney disease on hemodialysis (rapid iron replenishment needed)
5. Inflammatory anemia where oral iron is ineffective
6. Need for rapid iron replenishment (preoperative, severe anemia)
7. Functional iron deficiency in cancer patients on erythropoiesis-stimulating agents (ESAs)

• IV iron sucrose: 200-300 mg in 100-250 mL NS infused over 15-30 min.
• Test dose: 25 mg IV over 15 min (for iron dextran), observe 30 min before full dose.
• Total dose infusion (TDI): Calculated as: Total iron deficit (mg) = Weight (kg) × [Target Hb - Actual Hb (g/dL)] × 2.4 + 500 (storage iron).
  • Ferric carboxymaltose can deliver up to 1000 mg in a single infusion.

• Inject deep IM in upper outer quadrant of buttock using Z-track technique (skin pulled laterally before injection, released after) → prevents leakage into subcutaneous tissue, staining.
• 1.5-inch needle, 19-20 gauge; change needle after drawing up.
• NOT recommended IV (unlike iron dextran).

1. Anaphylaxis/Hypersensitivity (most serious):
   • Highest risk with iron dextran (high MW).
   • Management: Epinephrine, antihistamines, corticosteroids; resuscitation facilities must be available.
2. Arthralgia, myalgia (DIOS - delayed infusion reaction) with high-dose IV iron (ferric carboxymaltose, iron dextran) - 24-48 h post-infusion; self-limiting.
3. Hypotension - with rapid infusion (free iron in plasma → vasodilation, oxidative stress).
4. Fever, chills, nausea, vomiting - more common with iron dextran.
5. Local reactions (IM):
   • Pain at injection site
   • Permanent brown skin staining (hemosiderin deposition) - if technique improper
   • Sarcoma formation at injection site (iron dextran IM - rare, long-term concern)
6. Hemosiderosis/Iron overload - if given in excess; avoid in hemochromatosis.
7. Thrombophlebitis - at IV site.
8. Hypophosphatemia (ferric carboxymaltose-specific) - impairs renal tubular phosphate reabsorption.

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Q3.3 — Leprosy (38-year-old male, slit-skin smear positive for M. leprae)

(a) Pharmacotherapy (3 marks)

• Duration: 6 months
• Rifampicin 600 mg once monthly (supervised) + Dapsone 100 mg daily

• Rifampicin 600 mg + Ofloxacin 400 mg + Minocycline 100 mg (once).

• Rifampicin: Inhibits bacterial RNA polymerase (beta subunit) → blocks RNA synthesis → bactericidal. Most powerful anti-leprosy drug; kills > 99.9% bacilli in 1-2 doses.
• Dapsone (DDS - 4,4'-diaminodiphenyl sulfone): Sulfonamide analogue; inhibits dihydropteroate synthase → blocks folate synthesis in M. leprae → bacteriostatic. Also anti-inflammatory (used in PCP prophylaxis, dermatitis herpetiformis).
• Clofazimine: Binds to guanine bases in mycobacterial DNA → inhibits template function; also anti-inflammatory (through generation of reactive oxygen species, inhibits M. leprae phospholipase A2). Slowly bactericidal. Also suppresses ENL (erythema nodosum leprosum) reactions.

• Type 1 (Reversal reaction): Prednisolone 40-60 mg/day.
• Type 2 (ENL - Erythema Nodosum Leprosum): Thalidomide (drug of choice for males) 100-300 mg/day; Prednisolone (first-line in general); Clofazimine 300 mg/day.

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(b) Adverse Drug Reactions (2 marks)

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Q3.4 — Adverse Drug Reactions of Anti-Cancer Drugs (5 marks)

1. Bone marrow suppression (myelosuppression) - most common class effect of all cytotoxics; neutropenia (nadir 7-14 days), thrombocytopenia, anemia → risk of infections, bleeding.
2. Nausea and vomiting (CINV) - Cisplatin: most emetogenic; managed with ondansetron + dexamethasone + aprepitant (NK1 antagonist).
3. Hemorrhagic cystitis (Cyclophosphamide, Ifosfamide) - acrolein metabolite damages urothelium; prevent with MESNA (mercaptoethanesulfonate sodium), aggressive hydration.
4. Nephrotoxicity (Cisplatin) - tubular damage; prevent with IV hydration, amifostine; monitor creatinine.
5. Peripheral neuropathy (Cisplatin, Vincristine, Oxaliplatin) - sensory > motor.
6. Ototoxicity (Cisplatin) - high-frequency hearing loss; tinnitus.
7. Pulmonary fibrosis (Bleomycin, Busulfan, Carmustine) - interstitial fibrosis; dose-limiting for bleomycin.
8. Cardiotoxicity (Doxorubicin/Anthracyclines) - dose-dependent cardiomyopathy (cumulative dose >450 mg/m2); preventable with Dexrazoxane.
9. Secondary malignancies (alkylating agents) - leukemia, lymphoma years later.

1. Mucositis/stomatitis (Methotrexate, 5-FU) - painful oral ulcers; leucovorin rescue for methotrexate toxicity.
2. GI toxicity - diarrhea (5-FU), nausea.
3. Myelosuppression - especially 5-FU, cytarabine.
4. Hepatotoxicity (Methotrexate, 6-MP).
5. Hand-foot syndrome (palmar-plantar erythrodysesthesia) - 5-FU, Capecitabine.
6. Alopecia - most prominent with doxorubicin, cyclophosphamide; reversible.

1. Vincristine: Peripheral neuropathy (DOSE-LIMITING), constipation, autonomic neuropathy (ileus, urinary retention), cranial nerve palsies. MINIMAL myelosuppression (unlike most cytotoxics).
2. Vinblastine: Myelosuppression (DOSE-LIMITING) + neuropathy.
3. Fatal if given intrathecally (vincristine) - NEVER administer IT.

1. Myelosuppression, peripheral neuropathy, alopecia, hypersensitivity reactions (paclitaxel - use premedication with dexamethasone + diphenhydramine + ranitidine), fluid retention (docetaxel), bradycardia.

1. Imatinib (BCR-ABL inhibitor): Edema, fluid retention, nausea, myelosuppression.
2. Trastuzumab (Anti-HER2): Cardiotoxicity (cardiomyopathy), infusion reactions.
3. Rituximab (Anti-CD20): Infusion reactions (fever, rigors, hypotension, bronchospasm), immunosuppression, progressive multifocal leukoencephalopathy (PML) - rare.
4. Checkpoint inhibitors (Pembrolizumab, Nivolumab): Immune-related adverse events (irAEs): pneumonitis, colitis, endocrinopathies (thyroiditis, adrenalitis), hepatitis, rash; treat with corticosteroids.

1. Tamoxifen: Increased risk of endometrial cancer, DVT/PE, hot flashes, vaginal discharge.
2. Aromatase inhibitors (Letrozole, Anastrozole): Osteoporosis, arthralgia, hot flashes.
3. Anti-androgens (Bicalutamide): Gynecomastia, liver toxicity.

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SECTION - B (Q-4: Short Answer - Any Four out of Five)

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Q4.1 — Drug Regimen for Eradication of H. pylori Infection (5 marks)

• PPI (standard dose BD) + Clarithromycin 500 mg BD + Amoxicillin 1 g BD
• Eradication rate: ~80-85% (declining due to clarithromycin resistance).

• PPI BD + Bismuth subcitrate 120 mg QID + Tetracycline 500 mg QID + Metronidazole 500 mg TDS (or QID)
• Eradication rate: ~90%.

• PPI + Clarithromycin + Amoxicillin + Metronidazole all given simultaneously.

• Days 1-5: PPI + Amoxicillin 1 g BD
• Days 6-10: PPI + Clarithromycin 500 mg BD + Tinidazole 500 mg BD
• Eradication ~90%; avoids clarithromycin-resistant strains formed when amoxicillin used first.

• PPI + Levofloxacin 500 mg OD + Amoxicillin 1 g BD
• Used when first-line fails.

• PPI + Rifabutin 150 mg BD + Amoxicillin 1 g BD
• For multiple treatment failures.

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Q4.2 — Post-Exposure Prophylaxis (PEP) of HIV (5 marks)

• Occupational exposure (needlestick, mucosal splash with HIV-positive blood/fluids)
• Non-occupational: unprotected sexual intercourse (rape, consensual), sharing needles with HIV+ person

• TDF (Tenofovir) 300 mg + FTC (Emtricitabine) 200 mg (as Truvada/Tenof-EM) once daily
• • DTG (Dolutegravir) 50 mg once daily
• Duration: 28 days

• TDF + 3TC (Lamivudine) 300 mg OD + Dolutegravir 50 mg OD
• OR TDF/FTC + Raltegravir (400 mg BD or 1200 mg OD)

• AZT (Zidovudine) 300 mg BD + 3TC 150 mg BD + LPV/r (Lopinavir/ritonavir) BD

1. First aid: Wash wound with soap and water ×5 min; flush mucosa with water/saline.
2. Assess source patient (HIV status, viral load) and nature of exposure.
3. Initiate PEP within 2 hours (max 72 hours).
4. Follow-up: HIV testing at baseline, 6 weeks, 12 weeks, 6 months; monitor for ART toxicity (nausea, headache, renal toxicity with TDF).

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Q4.3 — Methotrexate: Mechanism of Action and Therapeutic Uses (5 marks)

Mechanism of Action:

1. MTX enters cells via reduced folate carrier (RFC) → polyglutamated by folylpolyglutamate synthetase (FPGS) → MTX polyglutamates (retained intracellularly, more potent inhibitors).
2. Inhibits dihydrofolate reductase (DHFR): Binds with ~1000-fold higher affinity than folate → blocks conversion of dihydrofolate (DHF) to tetrahydrofolate (THF) → depletion of THF (active folate cofactor).
3. Consequences of THF depletion:
   • No 5,10-methylene-THF → cannot synthesize thymidylate from dUMP → blocks thymidylate synthase (TS) → reduced thymidine → inhibited DNA synthesis and repair.
   • No 10-formyl-THF → impaired purine synthesis (de novo) → reduced adenosine and guanosine → reduced DNA/RNA synthesis.
   • Result: Cell cycle arrest at S phase → cell death (most toxic to rapidly dividing cells).

• MTX polyglutamates also inhibit AICAR transformylase → accumulation of AICAR → stimulates release of extracellular adenosine → adenosine acts on A2 receptors on immune cells → suppresses TNF-alpha, IL-1, IL-6, IL-8 → anti-inflammatory. This is the PRIMARY mechanism for its anti-inflammatory/immunosuppressive use.

• Leucovorin (reduced folate) bypasses DHFR → restores THF → rescues normal tissues after high-dose MTX.
• Used after high-dose MTX in cancer (osteosarcoma, leukemia protocols).

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Therapeutic Uses:

1. Acute Lymphoblastic Leukemia (ALL) - intrathecal MTX for CNS prophylaxis/treatment
2. Non-Hodgkin's Lymphoma (NHL) - high-dose IV
3. Osteosarcoma - high-dose with leucovorin
4. Choriocarcinoma (gestational trophoblastic disease) - highly effective; may be curative as single agent
5. Head and neck cancers, breast cancer, lung cancer - combination regimens
6. Primary CNS lymphoma - high-dose IV MTX

1. Rheumatoid Arthritis - first-line DMARD; reduces disease activity, erosions, disability; gold standard non-biologic DMARD.
2. Psoriasis - for severe plaque, pustular, erythrodermic psoriasis; weekly low dose.
3. Psoriatic arthritis - DMARD of choice.
4. Juvenile Idiopathic Arthritis (JIA)
5. SLE (Systemic Lupus Erythematosus) - skin and joint involvement.
6. Inflammatory bowel disease - Crohn's disease (steroid-sparing).
7. Ectopic pregnancy - IM MTX (single or multiple dose) - ruptures fallopian tube ectopic; avoids surgery.
8. Medical termination of pregnancy - combined with misoprostol (medical abortion).
9. Asthma, dermatomyositis - steroid-sparing.

• Mucositis, hepatotoxicity, myelosuppression, pulmonary toxicity (interstitial pneumonitis), teratogenicity (Category X - avoid in pregnancy), renal toxicity (high doses), nephrotoxicity.
• Leucovorin rescue prevents toxicity; folic acid 1 mg/day supplementation during low-dose weekly MTX reduces mucositis/hepatotoxicity.
• CONTRAINDICATED in pregnancy (Category X); pregnancy avoided for 3 months after stopping.

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Q4.4 — Treatment Regimen for Newly Diagnosed Drug-Sensitive Tuberculosis (5 marks)

WHO/RNTCP (Revised National TB Control Programme - India) Regimen:

• HRZE - Isoniazid (H) + Rifampicin (R) + Pyrazinamide (Z) + Ethambutol (E)
• Daily therapy for 2 months (56 doses).
• Given as Fixed-Dose Combination (FDC) tablets (reduces pill burden, prevents monotherapy, improves adherence).

• HR - Isoniazid + Rifampicin
• Daily therapy for 4 months (112 doses).

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Drug Doses (Adult, weight-based):

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Key Adverse Effects:

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Q4.5 — Nutraceuticals with Suitable Examples (5 marks)

Classification with Examples:

1. Vitamins: Vitamin C (ascorbic acid) - antioxidant, immune support; Vitamin D - bone health, immune modulation; Vitamin E - antioxidant.
2. Minerals: Calcium (bone health), Zinc (immune function, wound healing), Iron, Magnesium.
3. Amino acids: Glutamine (gut mucosal integrity), Arginine (precursor to NO, wound healing), BCAAs (branched chain amino acids - muscle preservation).

1. Curcumin (Turmeric): Anti-inflammatory (inhibits NF-kB, COX-2, LOX), antioxidant, cancer-preventive (investigated in colon cancer).
2. Ginkgo biloba: Improves peripheral and cerebral circulation (used for dementia, tinnitus); inhibits PAF.
3. Echinacea: Immune stimulant; reduces duration of common cold.
4. Garlic (Allicin): Antimicrobial, antithrombotic, antihypertensive, lowers LDL.
5. Green tea polyphenols (EGCG): Antioxidant, anti-cancer (chemopreventive), antiobesity.
6. St. John's Wort (Hypericum perforatum): Antidepressant (inhibits serotonin, NE, dopamine reuptake); caution - major drug interactions (CYP3A4 inducer).

1. Probiotics: Live microorganisms (Lactobacillus, Bifidobacterium) conferring health benefits; prevent/treat diarrhea, restore gut flora post-antibiotics, IBD.
2. Prebiotics: Non-digestible fibers (inulin, FOS - fructooligosaccharides) that feed beneficial gut bacteria.
3. Omega-3 fatty acids (EPA, DHA): Fish oil; reduce TG by 50%, anti-inflammatory, cardioprotective (prevent arrhythmias); approved drugs: Icosapent ethyl (Vascepa) for hypertriglyceridemia.
4. Plant sterols/stanols: Added to margarine (Benecol, Flora); inhibit intestinal cholesterol absorption by competing with cholesterol for incorporation into micelles → reduce LDL by 10-15%.
5. Lycopene (tomatoes): Carotenoid antioxidant; may reduce prostate cancer risk.

1. Resveratrol (red wine): Activates SIRT1 deacetylase; antioxidant; possible anti-aging, cardioprotective.
2. Coenzyme Q10 (Ubiquinone): Component of mitochondrial electron transport chain; antioxidant; used for heart failure, statin-induced myopathy.
3. Glucosamine and Chondroitin sulfate: Structural components of cartilage; used for osteoarthritis (mild symptom relief, evidence mixed).
4. Melatonin: Sleep hormone; used for insomnia, jet lag, circadian rhythm disorders.
5. Lutein and Zeaxanthin: Carotenoids; protective against age-related macular degeneration (AMD) and cataracts.

• Regulated under FSSAI (Food Safety and Standards Authority of India) as "health supplements."
• Not regulated as drugs (CDSCO) → efficacy and safety claims less strictly validated than pharmaceuticals.
• Increasing role in preventive healthcare and chronic disease management.

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SECTION - C (Q-5: Short Answer - Choice within each question)

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Q5.1 — Mechanism of Action and Therapeutic Uses of Penicillin G (5 marks)

Mechanism of Action:

• Penicillin G is a beta-lactam + thiazolidine ring (6-APA nucleus).
• Enters gram-positive bacteria directly through cell wall; in gram-negative bacteria, passes through porin channels (OmpF, OmpC) in outer membrane.

• PBPs are enzymes on the inner membrane: transpeptidases, carboxypeptidases, endopeptidases.
• Penicillin G's beta-lactam ring is a structural analogue of the D-Ala-D-Ala terminus of the pentapeptide side chain of peptidoglycan precursors.
• Covalently binds to serine residue at the active site of PBPs → irreversible inhibition of transpeptidase activity.

• Transpeptidase normally cross-links peptidoglycan chains: D-Ala-D-Ala + Gly bridge → cross-link (loss of terminal D-Ala).
• Inhibition of transpeptidase → no cross-linking of peptidoglycan → weakened, structurally unstable cell wall.

• Activated autolysins (murein hydrolases) cleave existing peptidoglycan (no longer inhibited by cross-linked mesh) → cell lysis.
• Bactericidal; time-dependent killing (efficacy depends on time drug concentration remains above MIC).

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Therapeutic Uses:

• Penicillin G (aqueous crystalline): IV/IM; short t½ (30 min); dosed q4-6h.
• Procaine penicillin G: IM depot; lasts 12-24 h.
• Benzathine penicillin G: IM depot; very slow release; lasts 2-4 weeks (for syphilis, rheumatic fever prophylaxis).

1. Hypersensitivity - most important; rashes, urticaria, serum sickness, anaphylaxis (0.01-0.05%); fatal anaphylaxis 1-2 per 100,000 injections; always ask allergy history; keep epinephrine ready.
2. Pain at IM injection site.
3. Neurotoxicity - high IV doses (>20 MU/day) → seizures, encephalopathy (especially in renal failure - drug accumulates).
4. Electrolyte imbalance - Penicillin G sodium (causes hypernatremia in large doses), or hypokalemia (renal tubular secretion of K+).
5. Jarisch-Herxheimer reaction - in syphilis treatment; sudden fever, rigors, hypotension 2-8 hours after first dose; due to release of spirochetal antigens; managed with aspirin.
6. Superinfection - Candida overgrowth.

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Q5.1 (OR) — Artemisinin-Based Combination Therapy (ACT) (5 marks)

• Artemisinin contains an endoperoxide bridge → reacts with heme (ferroprotoporphyrin IX) in the food vacuole of Plasmodium → cleavage of peroxide bond by Fe2+ in heme → generates highly reactive free radicals (carbon-centered, oxygen-centered) → alkylate and damage parasite proteins, membranes, DNA → rapid parasite death.
• Kills all asexual stages including young ring forms and gametocytes (reduces transmission).
• Acts within hours; reduces parasite load by 10,000-fold per cycle.

• Artemisinin has short half-life (1-4 hours) → rapidly cleared → if used alone, surviving parasites could recrudescence.
• ACT: Artemisinin rapidly reduces parasite biomass (acts in first 3 days) + Partner drug (longer half-life) eliminates remaining parasites → cure + prevents resistance.
• Prevents emergence of resistance to either drug.

• IV/IM Artesunate - drug of choice (replaced quinine); 2.4 mg/kg IV at 0, 12, 24 h then daily.
• Switch to oral ACT when patient can swallow.

• Artesunate (water-soluble; IV/IM/oral/rectal), Artemether (oil-soluble; IM/oral), Dihydroartemisinin (DHA - active metabolite of all).
• Half-life: 1-4 hours (artesunate), 2-3 hours (DHA).

• Lumefantrine: Blocks heme detoxification → accumulation of toxic heme → parasite death; t½ 3-6 days; taken with fatty food for absorption.
• Piperaquine: Bisquinoline; accumulates in food vacuole; very long t½ (2-3 weeks) → single 3-day course effective.

1. Artemisinin compounds: Generally well-tolerated; neurotoxicity (animal studies, not established in humans at therapeutic doses); transient bradycardia/QTc prolongation; mild GI effects; transient bone marrow suppression.
2. Lumefantrine: QTc prolongation (cardiac monitoring); GI side effects.
3. Mefloquine: Neuropsychiatric effects (anxiety, vivid dreams, psychosis, seizures), dizziness.
4. Amodiaquine: Agranulocytosis (with prolonged use as prophylaxis - NOT recommended for prophylaxis), hepatotoxicity.
5. Piperaquine: QTc prolongation.

• First trimester: Data limited; benefit-risk assessment; WHO currently advises quinine + clindamycin for first trimester.
• Second and third trimester: ACT preferred (AL or ASPY); artesunate + clindamycin for first trimester severe malaria.

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Q5.2 — Patient Autonomy: Definition and Doctor's Responsibilities (5 marks)

1. Autonomy - respect for patient's self-determination
2. Beneficence - acting in patient's best interest
3. Non-maleficence - avoiding harm
4. Justice - fair treatment

1. Informed consent: Patient must receive complete, accurate, comprehensible information about diagnosis, treatment options, benefits, risks, alternatives, and consequences of refusing.
2. Right to refuse treatment: Even life-saving treatment; a competent adult can refuse.
3. Right to choose among options: Patient chooses among medically reasonable alternatives.
4. Confidentiality: Patient controls disclosure of their health information.
5. Advance directives: Written instructions (living will, healthcare proxy) when patient may be unable to decide later.

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Doctor's Responsibilities While Respecting Patient Autonomy:

1. Provide complete and honest information:
   • Give accurate diagnosis, prognosis, treatment options, benefits, risks, and alternatives in understandable language.
   • Avoid medical jargon; use interpreters when needed.
2. Obtain valid informed consent:
   • Consent must be: Informed (adequate information given), Voluntary (no coercion), Competent (patient has decision-making capacity).
   • Document consent properly.
3. Assess decision-making capacity:
   • Verify the patient understands information, appreciates consequences, reasons consistently, communicates a choice.
   • If incapacitated (coma, dementia): consult surrogate decision-maker (family/legal guardian).
4. Respect decisions even when disagreeing:
   • If a competent patient refuses a recommended treatment, the doctor must respect this decision.
   • Document refusal (Against Medical Advice - AMA) properly.
5. Do not abandon the patient:
   • Even if the patient refuses, continue to provide palliative care and support; explore reasons for refusal.
6. Protect vulnerable patients:
   • Special care for minors (parental consent + assent of older children), pregnant women, cognitively impaired, prisoners, the elderly.
7. Avoid paternalism:
   • Paternalism = overriding patient's wishes "for their own good." Acceptable only in emergencies when patient is unconscious and next-of-kin unavailable.
8. Maintain confidentiality:
   • Do not share patient information without consent; exceptions (mandatory reporting: STIs, TB, occupational diseases; court orders).
9. Advance care planning:
   • Help patients document advance directives; respect do-not-resuscitate (DNR) orders.
10. Cultural sensitivity:
    • Recognize cultural and religious values affecting decisions; respect without judgment.

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Q5.2 (OR) — Shared Decision-Making and Its Importance (5 marks)

• Clinical expertise (what medicine can offer) + Patient's values and preferences (what matters to the patient).

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The 3-Step Model of SDM (Elwyn et al.)

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Importance of Shared Decision-Making:

1. Respects patient autonomy: Ensures patients make decisions aligned with their own values, not just physician preferences.
2. Improves treatment adherence: Patients who participate in decisions are more likely to follow through with chosen treatment → better outcomes.
3. Improves patient satisfaction: Patients feel heard and respected → better therapeutic relationship.
4. Reduces decisional regret: Patients are more at peace with outcomes when they made an informed, participatory choice.
5. Better health outcomes: Evidence shows SDM improves outcomes in chronic diseases (diabetes, hypertension, cancer screening decisions).
6. Appropriate use of healthcare resources: Patients often choose less invasive, less expensive options when fully informed → reduces overtreatment.
7. Ethical obligation: Mandated by principles of autonomy and beneficence; required by MCI/NMC guidelines for informed consent.
8. Reduces medicolegal risk: Documented SDM protects physician in cases of adverse outcomes.
9. Particularly important for:
   • Preference-sensitive conditions (where options have different tradeoffs - e.g., mastectomy vs. lumpectomy for breast cancer; knee replacement vs. physiotherapy)
   • Chronic disease management (long-term medication choices)
   • End-of-life decisions
   • Screening decisions (PSA, mammography - where benefits and harms are finely balanced)
10. Challenges: Time constraints in clinical practice, low health literacy of patients, cultural barriers, clinician discomfort with uncertainty, inadequate training.

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