Pharm.D. Doctor of Pharmacy Drug Interactions and Adverse Effects 2 — Questions and Answers
Question 1: Which adverse effect is associated with clozapine use that requires mandatory weekly or biweekly CBC monitoring?
- Hepatotoxicity
- Agranulocytosis (Correct answer)
- Ototoxicity
- Rhabdomyolysis
Correct answer: Agranulocytosis
Clozapine is associated with life-threatening agranulocytosis (severe neutropenia), requiring mandatory CBC monitoring under the Clozapine REMS program.
Question 2: A patient on lithium develops polyuria, tremor, and confusion after starting ibuprofen. What interaction has occurred?
- Ibuprofen induces lithium metabolism, lowering levels
- Ibuprofen reduces renal lithium clearance, causing lithium toxicity (Correct answer)
- Ibuprofen blocks lithium's CNS effects directly
- This combination improves lithium efficacy
Correct answer: Ibuprofen reduces renal lithium clearance, causing lithium toxicity
NSAIDs inhibit prostaglandin-mediated renal blood flow, reducing renal lithium clearance and causing lithium accumulation and toxicity.
Question 3: Which adverse effect is specifically associated with tetracycline use in children under 8 years of age?
- Graying of the hair
- Permanent discoloration of developing teeth and enamel hypoplasia (Correct answer)
- Stunted growth of long bones
- Premature closure of growth plates
Correct answer: Permanent discoloration of developing teeth and enamel hypoplasia
Tetracyclines chelate calcium and deposit in developing bones and teeth, causing permanent yellow-brown discoloration of teeth and enamel hypoplasia in children under 8.
Question 4: Serotonin syndrome is most likely to occur with which combination?
- Metoprolol + atenolol
- Tramadol + sertraline (SSRI) (Correct answer)
- Metformin + lisinopril
- Amlodipine + atorvastatin
Correct answer: Tramadol + sertraline (SSRI)
Tramadol (has serotonergic and opioid properties) combined with an SSRI like sertraline creates excess serotonin activity, precipitating serotonin syndrome.
Question 5: QT prolongation caused by certain drugs increases the risk of which potentially fatal arrhythmia?
- Atrial fibrillation
- Ventricular fibrillation secondary to torsades de pointes (TdP) (Correct answer)
- First-degree AV block
- Sinus bradycardia
Correct answer: Ventricular fibrillation secondary to torsades de pointes (TdP)
Drug-induced QT prolongation can precipitate torsades de pointes (TdP), a polymorphic ventricular tachycardia that can degenerate into ventricular fibrillation and sudden cardiac death.
Question 6: Which adverse drug reaction is classified as a Type B (idiosyncratic) reaction?
- Aspirin-induced gastric ulcer
- Penicillin-induced anaphylaxis (Correct answer)
- Warfarin-induced bleeding at supratherapeutic levels
- Metformin-induced GI upset
Correct answer: Penicillin-induced anaphylaxis
Penicillin anaphylaxis is a Type B (idiosyncratic/immunological) reaction — it is unpredictable, not dose-related, and occurs in only susceptible individuals due to immune-mediated mechanisms.
Pharm.D. Doctor of Pharmacy Drug Interactions and Adverse Effects 2
Which adverse effect is associated with clozapine use that requires mandatory weekly or biweekly CBC monitoring?