Pharm.D. Doctor of Pharmacy Drug Interactions and Adverse Effects

Question 1

Which mechanism explains the interaction between rifampin and oral contraceptives?

Accepted Answer

Rifampin induces CYP3A4, accelerating estrogen metabolism and reducing contraceptive efficacy

Answer

Rifampin inhibits CYP3A4, increasing contraceptive levels

Answer

Rifampin competes for protein binding with estrogen

Answer

Rifampin blocks gut absorption of hormonal contraceptives

Question 2

Which adverse effect is specifically associated with aminoglycoside antibiotics and requires regular monitoring?

Accepted Answer

Nephrotoxicity and ototoxicity

Answer

Hepatotoxicity and elevated LFTs

Answer

Pulmonary fibrosis

Answer

Stevens-Johnson syndrome

Question 3

A patient on sildenafil is prescribed a nitrate for angina. What is the primary concern?

Accepted Answer

Severe hypotension due to additive vasodilation

Answer

Reduced sildenafil efficacy

Answer

Increased risk of priapism

Answer

Nitrate tolerance develops faster

Question 4

Which adverse effect is most concerning with long-term proton pump inhibitor (PPI) use?

Accepted Answer

Hypomagnesemia and increased risk of Clostridioides difficile infection

Answer

Hepatotoxicity

Answer

Renal tubular acidosis

Answer

Peripheral neuropathy

Question 5

Which lab finding is characteristic of heparin-induced thrombocytopenia (HIT)?

Accepted Answer

Platelet count drop of ≥50% from baseline, typically 5–14 days after heparin initiation

Answer

Elevated platelet count above 500,000/μL

Answer

White blood cell count below 2,000/μL

Answer

Elevated D-dimer with normal platelet count

Question 6

Which drug interaction mechanism is responsible for the increased bleeding risk when NSAIDs are combined with anticoagulants?

Accepted Answer

NSAIDs inhibit platelet aggregation and may displace anticoagulants from protein binding sites

Answer

NSAIDs induce CYP2C9, increasing anticoagulant metabolism

Answer

NSAIDs decrease vitamin K production

Answer

NSAIDs increase anticoagulant renal clearance