Pharmacovigilance and Medication Safety
Core concepts
Know the definitions: adverse drug reaction (ADR), adverse event, side effect, medication error, and near miss. Understand causality assessment concepts (temporal relationship, dechallenge, rechallenge, alternative explanations) and reporting systems. Seriousness criteria - death, hospitalisation, disability, congenital anomaly, life-threatening - must be recognised. Understand the difference between type A (dose-dependent, predictable) and type B (idiosyncratic, unpredictable) reactions. Know high-alert medications, look-alike/sound-alike risks, and the hierarchy of effectiveness for error prevention (forcing functions > constraints > automation > standardisation > education).
Traps in questions
- Reporting only serious events; non-serious ADRs also contribute to signal detection.
- Confusing a side effect with a medication error.
- Assuming a reaction is unrelated because the drug has been used for years.
- Treating education alone as sufficient error prevention.
Worked example / rule of thumb
A patient develops angioedema after starting a new ACE inhibitor, with no other new medicines. The reaction is temporally plausible, resolves on withdrawal, and recurs on rechallenge - strong causality. Rule of thumb: apply the "who, what, when, why" test - who took what, what happened, when did it occur relative to the drug, and what else could explain it?