PSI Pharmacology & Therapeutics 3 — Questions and Answers
Question 1: Which inhaler technique is most important for pressurised metered dose inhalers (pMDIs)?
- Slow, deep inhalation coordinated with actuation (Correct answer)
- Fast, forceful inhalation
- Holding the inhaler vertically downwards
- No breath-hold required
Correct answer: Slow, deep inhalation coordinated with actuation
Slow, deep inhalation coordinated with actuation maximises drug deposition in the lower airways. Fast inhalation causes impaction in the oropharynx, and a 10-second breath-hold improves deposition.
Question 2: Theophylline has a narrow therapeutic index. Which interaction significantly increases its toxicity risk?
- Ciprofloxacin inhibits CYP1A2, raising theophylline levels (Correct answer)
- Rifampicin raises theophylline levels
- Antacids reduce theophylline levels
- Warfarin has no effect on theophylline
Correct answer: Ciprofloxacin inhibits CYP1A2, raising theophylline levels
Ciprofloxacin is a strong CYP1A2 inhibitor. Theophylline is metabolised by CYP1A2; co-administration can double plasma levels, causing nausea, arrhythmias and seizures.
Question 3: Insulin glargine differs from human insulin because it:
- Has a prolonged, peakless action lasting ~24 hours (Correct answer)
- Has a rapid onset within 15 minutes
- Is given orally
- Cannot be mixed with other insulins (this is shared with human insulin)
Correct answer: Has a prolonged, peakless action lasting ~24 hours
Glargine has substitutions that create microcrystals at physiological pH, releasing insulin slowly with no pronounced peak — ideal as once-daily basal insulin.
Question 4: Which antiplatelet drug requires hepatic activation by CYP2C19 to exert its effect?
- Clopidogrel (Correct answer)
- Aspirin
- Ticagrelor
- Dipyridamole
Correct answer: Clopidogrel
Clopidogrel is a prodrug requiring CYP2C19-mediated activation. Poor metabolisers of CYP2C19 have reduced antiplatelet effect, increasing cardiovascular risk.
Question 5: Serotonin syndrome is most likely when combining an SSRI with which other drug?
- Linezolid (MAO inhibitor) (Correct answer)
- Atenolol
- Metformin
- Amlodipine
Correct answer: Linezolid (MAO inhibitor)
Linezolid inhibits monoamine oxidase (MAO), reducing serotonin breakdown. Combined with an SSRI, serotonin accumulates, causing hyperthermia, clonus, agitation and autonomic instability.
Question 6: Which class of drug is a GLP-1 receptor agonist used in type 2 diabetes?
- Semaglutide (Correct answer)
- Sitagliptin
- Empagliflozin
- Glibenclamide
Correct answer: Semaglutide
Semaglutide is a GLP-1 receptor agonist that stimulates glucose-dependent insulin secretion, suppresses glucagon, slows gastric emptying and reduces appetite.
PSI Pharmacology & Therapeutics 3
Which inhaler technique is most important for pressurised metered dose inhalers (pMDIs)?