PSI Pharmacology & Therapeutics 1 — Questions and Answers
Question 1: Which class of antihypertensives is the first-line treatment in patients with heart failure with reduced ejection fraction (HFrEF)?
- ACE inhibitors (Correct answer)
- Calcium channel blockers
- Alpha-1 blockers
- Direct vasodilators
Correct answer: ACE inhibitors
ACE inhibitors (e.g., ramipril, lisinopril) reduce mortality and morbidity in HFrEF by blocking angiotensin II production, reducing cardiac afterload and preload.
Question 2: Aspirin's antiplatelet effect is due to irreversible inhibition of which enzyme?
- COX-1 (cyclooxygenase-1) (Correct answer)
- COX-2
- Thrombin
- Phosphodiesterase
Correct answer: COX-1 (cyclooxygenase-1)
Aspirin irreversibly acetylates COX-1 in platelets, blocking thromboxane A2 synthesis. Because platelets lack nuclei, they cannot regenerate COX-1, so the effect lasts the platelet's 7–10 day lifespan.
Question 3: Which opioid is considered a partial agonist at the mu-opioid receptor?
- Buprenorphine (Correct answer)
- Morphine
- Fentanyl
- Oxycodone
Correct answer: Buprenorphine
Buprenorphine is a partial agonist at the mu-opioid receptor with high receptor affinity. Its ceiling effect on respiratory depression makes it safer in overdose than full agonists.
Question 4: The main mechanism of action of metformin in type 2 diabetes is:
- Reduction of hepatic glucose output (Correct answer)
- Stimulation of insulin secretion
- Inhibition of intestinal glucose absorption only
- Increasing renal glucose excretion
Correct answer: Reduction of hepatic glucose output
Metformin primarily activates AMPK, reducing hepatic gluconeogenesis and glycogenolysis, thereby decreasing fasting blood glucose. It does not cause hypoglycaemia alone.
Question 5: Which beta-blocker is cardioselective (beta-1 selective) at normal doses?
- Bisoprolol (Correct answer)
- Propranolol
- Carvedilol
- Labetalol
Correct answer: Bisoprolol
Bisoprolol (and atenolol, metoprolol) selectively block beta-1 adrenergic receptors at therapeutic doses, minimising bronchospasm risk compared to non-selective beta-blockers.
Question 6: Warfarin's anticoagulant effect is reversed most quickly by administering:
- Vitamin K and prothrombin complex concentrate (PCC) (Correct answer)
- Protamine sulphate
- Idarucizumab
- Fresh frozen plasma alone
Correct answer: Vitamin K and prothrombin complex concentrate (PCC)
For urgent reversal of warfarin, IV vitamin K plus PCC (containing factors II, VII, IX, X) restores clotting factors immediately. Vitamin K alone takes 6–12 hours to work.
PSI Pharmacology & Therapeutics 1
Which class of antihypertensives is the first-line treatment in patients with heart failure with reduced ejection fraction (HFrEF)?