DHA Pharmacist Clinical Pharmacology 2

Question 1

What is the clinical significance of first-pass metabolism for oral drug administration?

Accepted Answer

It reduces the bioavailability of oral drugs by metabolising them in the gut wall and liver before reaching systemic circulation

Answer

First-pass metabolism by gut wall enzymes and hepatic CYP450 enzymes can substantially reduce the amount of oral drug reaching systemic circulation, requiring higher oral doses compared to IV routes.

Question 2

A patient with renal impairment (GFR 20 mL/min) is prescribed gentamicin. Why is dose adjustment needed?

Accepted Answer

Gentamicin is renally excreted; reduced GFR causes drug accumulation leading to nephrotoxicity and ototoxicity

Answer

Gentamicin is almost entirely eliminated by glomerular filtration; reduced GFR leads to drug accumulation, increasing plasma levels and the risk of nephrotoxicity and irreversible ototoxicity.

Question 3

Which drug class is used as the antidote for benzodiazepine overdose?

Accepted Answer

Flumazenil (GABA-A receptor antagonist)

Answer

Flumazenil competitively antagonises benzodiazepine binding at the GABA-A receptor, rapidly reversing sedation, respiratory depression, and other CNS effects of benzodiazepine overdose.

Question 4

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

Accepted Answer

Beta-lactams (penicillins, cephalosporins, carbapenems)

Answer

Beta-lactam antibiotics bind to penicillin-binding proteins (PBPs) on the bacterial surface, blocking transpeptidation and cross-linking of peptidoglycan chains, leading to cell wall lysis.

Question 5

What is the primary mechanism by which statins lower LDL cholesterol?

Accepted Answer

Competitive inhibition of HMG-CoA reductase, reducing hepatic cholesterol synthesis and upregulating LDL receptors

Answer

Statins inhibit HMG-CoA reductase, the rate-limiting enzyme in hepatic cholesterol synthesis, causing compensatory upregulation of LDL receptors that clear LDL from the blood.

DHA Pharmacist Practice Test

DHA Pharmacist Practice Test

DHA Pharmacist Clinical Pharmacology 2