MBBS Pharmacology

Question 1

Which antibiotic class inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs)?

Accepted Answer

Beta-lactams

Answer

Beta-lactam antibiotics (penicillins, cephalosporins, carbapenems) inhibit cell wall synthesis by irreversibly binding to PBPs, preventing peptidoglycan cross-linking.

Question 2

Which drug is a competitive antagonist at the beta-1 adrenergic receptor used in heart failure?

Accepted Answer

Metoprolol

Answer

Metoprolol is a cardioselective beta-1 blocker that reduces heart rate and myocardial oxygen demand, improving outcomes in heart failure with reduced ejection fraction.

Question 3

The mechanism of action of statins involves inhibition of which enzyme?

Accepted Answer

HMG-CoA reductase

Answer

Statins inhibit HMG-CoA reductase, the rate-limiting enzyme in cholesterol synthesis, leading to upregulation of LDL receptors and decreased plasma LDL.

Question 4

Which opioid analgesic has the highest oral bioavailability and is often used in opioid maintenance therapy?

Accepted Answer

Methadone

Answer

Methadone has high oral bioavailability (~80%), a long half-life, and is used in opioid use disorder maintenance therapy.

Question 5

Which antiepileptic drug acts by prolonging the inactivation state of voltage-gated sodium channels?

Accepted Answer

Phenytoin

Answer

Phenytoin stabilizes the inactive state of voltage-gated Na+ channels, preventing rapid repetitive neuronal firing without affecting normal neural function.

MBBS - Bachelor of Medicine and Bachelor of Surgery Practice Test

MBBS - Bachelor of Medicine and Bachelor of Surgery Practice Test

MBBS Pharmacology