MBBS Pharmacology 2 — Questions and Answers
Question 1: Which of the following is the reversal agent for heparin toxicity?
- Vitamin K
- Fresh frozen plasma
- Protamine sulfate (Correct answer)
- Tranexamic acid
Correct answer: Protamine sulfate
Protamine sulfate is a positively charged molecule that binds and neutralizes negatively charged heparin, reversing its anticoagulant effect.
Question 2: Which diuretic acts on the thick ascending limb of the loop of Henle?
- Hydrochlorothiazide
- Furosemide (Correct answer)
- Spironolactone
- Acetazolamide
Correct answer: Furosemide
Furosemide is a loop diuretic that inhibits the Na-K-2Cl cotransporter (NKCC2) in the thick ascending limb, producing potent diuresis.
Question 3: Which antimalarial drug can cause hemolytic anemia in patients with G6PD deficiency?
- Chloroquine
- Mefloquine
- Primaquine (Correct answer)
- Artemether
Correct answer: Primaquine
Primaquine generates reactive oxygen species that cause hemolysis in G6PD-deficient patients who cannot regenerate NADPH to protect red blood cells.
Question 4: Warfarin's anticoagulant effect is due to inhibition of which enzyme?
- Thrombin
- Factor Xa
- Vitamin K epoxide reductase (Correct answer)
- Antithrombin III
Correct answer: Vitamin K epoxide reductase
Warfarin inhibits vitamin K epoxide reductase, preventing regeneration of reduced vitamin K needed for carboxylation of clotting factors II, VII, IX, and X.
Question 5: Which drug class is used as first-line treatment for type 2 diabetes and acts by reducing hepatic glucose production?
- Sulfonylureas
- Thiazolidinediones
- Biguanides (Metformin) (Correct answer)
- DPP-4 inhibitors
Correct answer: Biguanides (Metformin)
Metformin (a biguanide) primarily reduces hepatic gluconeogenesis by activating AMPK and is first-line therapy for type 2 diabetes.
Question 6: Which antipsychotic is associated with agranulocytosis and requires mandatory blood count monitoring?
- Haloperidol
- Olanzapine
- Clozapine (Correct answer)
- Risperidone
Correct answer: Clozapine
Clozapine causes agranulocytosis in 1–2% of patients, requiring weekly CBC monitoring for the first 6 months then bi-weekly.
MBBS Pharmacology 2
Which of the following is the reversal agent for heparin toxicity?