KAPS Pharmacology and Therapeutics 2

Question 1

A patient taking warfarin is started on fluconazole. What is the most likely pharmacokinetic mechanism behind the increased bleeding risk?

Accepted Answer

Inhibition of CYP2C9, reducing warfarin metabolism

Answer

Fluconazole inhibits CYP2C9, the primary enzyme responsible for S-warfarin metabolism, leading to elevated warfarin levels and increased anticoagulation.

Question 2

Which receptor mechanism is responsible for the therapeutic effect of beta-2 agonists in asthma?

Accepted Answer

Gs-coupled receptor activation increasing cAMP and causing bronchodilation

Answer

Beta-2 agonists activate Gs-coupled receptors, elevating intracellular cAMP, which activates protein kinase A and relaxes bronchial smooth muscle.

Question 3

A patient with stage 3 chronic kidney disease is prescribed metformin. What is the primary concern?

Accepted Answer

Lactic acidosis due to metformin accumulation

Answer

Metformin is renally cleared, and accumulation in CKD increases the risk of lactic acidosis, especially when eGFR falls below 30 mL/min/1.73m².

Question 4

Which pharmacodynamic principle explains why combining two opioid agonists rarely doubles the analgesic effect?

Accepted Answer

Receptor saturation at the mu-opioid receptor

Answer

Once mu-opioid receptors are saturated, adding a second full agonist produces little additional effect because the maximum receptor occupancy has been reached.

Question 5

A 70-year-old patient receives gentamicin for a gram-negative infection. Which dosing strategy best reduces nephrotoxicity?

Accepted Answer

Once-daily extended-interval dosing exploiting concentration-dependent killing

Answer

Extended-interval (once-daily) dosing achieves high bactericidal peaks while allowing trough levels to fall, reducing aminoglycoside accumulation in renal tubular cells.

(KAPS) Knowledge Assessment of Pharmaceutical Sciences Practice Test

(KAPS) Knowledge Assessment of Pharmaceutical Sciences Practice Test

KAPS Pharmacology and Therapeutics 2