Pharmacovigilance-themed clinical scenarios in a USMLE-style multiple-choice format, along with explanations. These questions will help focus on the pharmacovigilance processes, adverse drug reactions (ADRs), and regulatory aspects relevant to drug safety monitoring.
1. Drug-Induced Hepatotoxicity
A 55-year-old man presents with jaundice, fatigue, and elevated liver enzymes (AST and ALT) after starting a new medication for tuberculosis. His symptoms began two weeks after initiating treatment. Liver function tests show a pattern consistent with hepatocellular injury.
Question: Which drug is most likely responsible for his hepatotoxicity?
A) Isoniazid
B) Rifampin
C) Ethambutol
D) Streptomycin
E) Pyrazinamide
Answer: A) Isoniazid
Explanation: Isoniazid is known to cause drug-induced hepatotoxicity, particularly hepatocellular injury. Monitoring liver function tests is crucial in patients receiving isoniazid, and this is a well-known adverse drug reaction (ADR). In pharmacovigilance, these reports would be critical for early detection of drug-related liver injury.
2. Drug-Induced QT Prolongation
A 45-year-old woman is hospitalized with pneumonia and started on azithromycin. Two days later, she experiences palpitations and an EKG shows a prolonged QT interval. She has no prior cardiac history.
Question: Which of the following best explains the patient’s symptoms?
A) Ventricular fibrillation
B) Torsades de pointes
C) Atrial fibrillation
D) Sinus tachycardia
E) Atrioventricular block
Answer: B) Torsades de pointes
Explanation: Azithromycin is associated with prolongation of the QT interval, which can lead to Torsades de pointes, a potentially life-threatening arrhythmia. Drug-induced QT prolongation is a significant concern in pharmacovigilance, especially with antibiotics, antipsychotics, and antiarrhythmics.
3. Stevens-Johnson Syndrome
A 24-year-old female presents with a fever, malaise, and painful, peeling skin on her face and torso. She recently started on allopurinol for gout. On examination, she has erythematous macules with blistering and mucosal involvement.
Question: What is the most likely diagnosis?
A) Erythema multiforme
B) Contact dermatitis
C) Stevens-Johnson syndrome (SJS)
D) Psoriasis
E) Fixed drug eruption
Answer: C) Stevens-Johnson syndrome (SJS)
Explanation: Stevens-Johnson syndrome (SJS) is a severe cutaneous adverse reaction (SCAR) to drugs, with allopurinol being a known trigger. SJS requires immediate discontinuation of the offending drug, and reporting this ADR is crucial in pharmacovigilance systems to identify and monitor high-risk medications.
4. ACE Inhibitor-Induced Angioedema
A 60-year-old man presents to the emergency department with swelling of his lips and difficulty breathing. He started enalapril 5 days ago for hypertension. He has no history of allergies.
Question: What is the most likely cause of this patient’s symptoms?
A) Anaphylaxis
B) Angioedema
C) Urticaria
D) Bronchospasm
E) Laryngeal edema
Answer: B) Angioedema
Explanation: ACE inhibitors like enalapril are associated with angioedema, which is an adverse drug reaction (ADR) that can cause swelling of the lips, face, and airways. Monitoring and reporting such ADRs are essential in pharmacovigilance to prevent future occurrences in susceptible populations.
5. Drug-Induced Agranulocytosis
A 35-year-old woman is started on clozapine for treatment-resistant schizophrenia. Two weeks later, she presents with fever, sore throat, and malaise. Her CBC reveals a low white blood cell count, especially neutrophils.
Question: What is the most likely diagnosis?
A) Leukemia
B) Pancytopenia
C) Aplastic anemia
D) Agranulocytosis
E) Hemolytic anemia
Answer: D) Agranulocytosis
Explanation: Clozapine is associated with agranulocytosis, a life-threatening reduction in neutrophils. Regular blood monitoring is required for patients on clozapine, and pharmacovigilance ensures early detection and prevention of such severe adverse effects.
6. Rhabdomyolysis from Statins
A 60-year-old male on simvastatin presents with muscle pain, weakness, and dark-colored urine. His labs show elevated creatine kinase (CK) levels.
Question: What is the most likely complication?
A) Acute renal failure
B) Myocardial infarction
C) Pulmonary embolism
D) Rhabdomyolysis
E) Hemolytic anemia
Answer: D) Rhabdomyolysis
Explanation: Statins can cause rhabdomyolysis, which is characterized by muscle breakdown and elevated CK levels. Monitoring muscle symptoms in patients on statins is essential, and reporting such adverse reactions contributes to pharmacovigilance data collection.
7. Ototoxicity from Aminoglycosides
A 75-year-old woman is treated with gentamicin for a urinary tract infection. A few days into therapy, she reports dizziness, difficulty hearing, and ringing in her ears.
Question: What is the most likely adverse effect?
A) Nephrotoxicity
B) Ototoxicity
C) Tinnitus
D) Hearing loss
E) Vertigo
Answer: B) Ototoxicity
Explanation: Gentamicin, an aminoglycoside, is known to cause ototoxicity, particularly in the elderly. Regular auditory monitoring is recommended during aminoglycoside therapy, and pharmacovigilance systems track such serious adverse drug reactions.
8. Hypoglycemia from Sulfonylureas
A 50-year-old diabetic patient is found unconscious at home. His blood sugar on arrival is 30 mg/dL. His wife reports that he recently started taking glimepiride for diabetes.
Question: What is the most likely cause of his hypoglycemia?
A) Metformin
B) Glimepiride
C) Insulin
D) Acarbose
E) Pioglitazone
Answer: B) Glimepiride
Explanation: Sulfonylureas such as glimepiride can cause severe hypoglycemia as a side effect. Pharmacovigilance plays a crucial role in monitoring reports of hypoglycemia in patients on sulfonylureas to ensure appropriate dosing and use.
9. Hepatotoxicity from Methotrexate
A 45-year-old woman with rheumatoid arthritis presents with fatigue, jaundice, and elevated liver enzymes after 6 months of methotrexate therapy.
Question: What is the most likely adverse effect?
A) Drug-induced cholestasis
B) Hepatocellular carcinoma
C) Hepatitis
D) Hepatotoxicity
E) Cirrhosis
Answer: D) Hepatotoxicity
Explanation: Methotrexate is known to cause hepatotoxicity with long-term use, especially in higher doses. Liver function should be monitored regularly, and adverse effects should be reported to pharmacovigilance databases for tracking and risk assessment.
10. Anaphylaxis from Penicillin
A 30-year-old woman presents to the emergency department with shortness of breath, hives, and hypotension shortly after receiving a dose of penicillin for a sinus infection.
Question: What is the most likely diagnosis?
A) Angioedema
B) Anaphylaxis
C) Serum sickness
D) Urticaria
E) Bronchospasm
Answer: B) Anaphylaxis
Explanation: Penicillin can cause anaphylaxis, a severe, life-threatening allergic reaction. This requires immediate treatment and reporting to pharmacovigilance systems for post-marketing surveillance of allergic reactions associated with penicillin use.
