Pharmacology Flashcards

Which mechanism best describes the action of beta-lactam antibiotics?

Answer: Inhibit bacterial cell wall synthesis by binding penicillin-binding proteins

Beta-lactams inhibit transpeptidation by covalently binding penicillin-binding proteins (PBPs), preventing cross-linking of peptidoglycan.

A patient on warfarin is started on rifampin. What pharmacokinetic interaction is expected?

Answer: Decreased warfarin effect due to CYP induction

Rifampin is a potent CYP450 inducer that increases warfarin metabolism, significantly reducing its anticoagulant effect.

Which adrenergic receptor subtype mediates bronchodilation?

Answer: Beta-2

Beta-2 adrenergic receptors in bronchial smooth muscle mediate relaxation and bronchodilation when stimulated.

What is the primary mechanism of action of thiazide diuretics?

Answer: Inhibit Na+/Cl- cotransporter in the distal convoluted tubule

Thiazides inhibit the NCC (Na+/Cl-) cotransporter in the distal convoluted tubule, reducing sodium reabsorption.

A patient with opioid overdose presents with pinpoint pupils and respiratory depression. Which agent is the treatment of choice?

Answer: Naloxone

Naloxone is a competitive opioid antagonist at mu, kappa, and delta receptors and rapidly reverses opioid toxidrome.

Which antiepileptic drug acts primarily by blocking voltage-gated sodium channels in their inactivated state?

Answer: Phenytoin

Phenytoin stabilizes the inactivated state of voltage-gated Na+ channels, preventing repetitive neuronal firing.

ACE inhibitors are contraindicated in pregnancy primarily because they cause which fetal complication?

Answer: Renal dysgenesis and oligohydramnios

ACE inhibitors reduce fetal renal perfusion, leading to renal tubular dysgenesis, oligohydramnios, and fetal death, especially in the 2nd and 3rd trimester.