PSA Adverse Drug Reactions 2 — Questions and Answers
Question 1: Which classification system uses letters A through F to categorize adverse drug reactions by mechanism and predictability?
- WHO-UMC system
- Rawlins-Thompson classification (Correct answer)
- Naranjo algorithm
- DoTS classification
Correct answer: Rawlins-Thompson classification
The Rawlins-Thompson classification categorizes ADRs as Type A (augmented, dose-dependent) through Type F, describing mechanism and predictability.
Question 2: A patient develops widespread blistering with mucosal involvement and epidermal detachment affecting >30% of BSA after starting allopurinol. What is the most likely diagnosis?
- Stevens-Johnson syndrome
- Toxic epidermal necrolysis (Correct answer)
- Drug reaction with eosinophilia and systemic symptoms
- Erythema multiforme
Correct answer: Toxic epidermal necrolysis
Toxic epidermal necrolysis is defined by epidermal detachment affecting >30% of body surface area and is a life-threatening ADR most commonly triggered by allopurinol, sulfonamides, or anticonvulsants.
Question 3: A patient develops serotonin syndrome after starting tramadol while already prescribed sertraline. Which symptom triad is most characteristic?
- Bradycardia, hypothermia, and miosis
- Agitation, hyperthermia, and clonus (Correct answer)
- Hypotension, urinary retention, and constipation
- Somnolence, respiratory depression, and miosis
Correct answer: Agitation, hyperthermia, and clonus
Serotonin syndrome presents with the classic triad of neuromuscular excitability (clonus, hyperreflexia), autonomic instability, and altered mental status including agitation and hyperthermia.
Question 4: Which of the following drugs is LEAST likely to cause QTc interval prolongation?
- Clarithromycin
- Haloperidol
- Amiodarone
- Metformin (Correct answer)
Correct answer: Metformin
Metformin does not affect cardiac ion channels; QT-prolonging drugs include macrolide antibiotics, antipsychotics, and antiarrhythmics that block cardiac hERG potassium channels.
Question 5: A patient on isoniazid for tuberculosis develops jaundice and ALT 10 times the upper limit of normal. What pattern of drug-induced liver injury is this?
- Cholestatic hepatotoxicity
- Hepatocellular hepatotoxicity (Correct answer)
- Mixed pattern hepatotoxicity
- Drug-induced steatohepatitis
Correct answer: Hepatocellular hepatotoxicity
Isoniazid causes predominantly hepatocellular injury with markedly elevated ALT; it can progress to fulminant hepatic failure if not discontinued promptly upon recognition.
Question 6: Which reporting scheme should UK prescribers use to report suspected adverse drug reactions for marketed medicines?
- MedWatch
- Yellow Card scheme (Correct answer)
- EudraVigilance
- VAERS
Correct answer: Yellow Card scheme
The MHRA Yellow Card scheme is the UK pharmacovigilance system for reporting suspected ADRs to prescription medicines, over-the-counter products, and vaccines.
Question 7: A Type B adverse drug reaction is best characterized by which of the following features?
- Dose-dependent and predictable from pharmacology
- Idiosyncratic and unrelated to normal drug pharmacology (Correct answer)
- Occurs only after prolonged cumulative drug use
- Related to abrupt drug withdrawal
Correct answer: Idiosyncratic and unrelated to normal drug pharmacology
Type B (bizarre) reactions are unpredictable, not dose-dependent, and unrelated to the drug's known pharmacological actions, with penicillin anaphylaxis being the classic example.
PSA Adverse Drug Reactions 2
Which classification system uses letters A through F to categorize adverse drug reactions by mechanism and predictability?