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 is a potent CYP3A4 inducer that accelerates the hepatic metabolism of estrogen and progestin in oral contraceptives, significantly reducing their plasma levels and contraceptive efficacy.

Question 2

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

Accepted Answer

Nephrotoxicity and ototoxicity

Answer

Aminoglycosides (e.g., gentamicin, tobramycin) are associated with concentration-dependent nephrotoxicity and ototoxicity, requiring serum level monitoring and renal function assessment.

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

Both sildenafil (PDE5 inhibitor) and nitrates increase cGMP, causing profound additive vasodilation and potentially life-threatening hypotension — this combination is absolutely contraindicated.

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

Long-term PPI use is associated with hypomagnesemia, hypokalemia, increased risk of C. difficile infection, and reduced absorption of calcium, vitamin B12, and iron.

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

HIT is characterized by a ≥50% platelet count drop from baseline occurring 5–14 days after heparin initiation due to antibodies against heparin-platelet factor 4 complexes.

Pharm.D. Doctor of Pharmacy Practice Test

Pharm.D. Doctor of Pharmacy Practice Test

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