Adverse drug reactions (Rawlins–Thompson)
[object Object]
What it means
A — Augmented: dose-related, predictable extension of pharmacology (most common; e.g. insulin→hypoglycaemia, ACEi→AKI). B — Bizarre: idiosyncratic/immunological, not dose-related (anaphylaxis, malignant hyperthermia). C — Chronic (steroid osteoporosis). D — Delayed (teratogenesis, malignancy). E — End-of-use (withdrawal: β-blocker rebound, opioid/benzodiazepine, steroid). F — Failure of therapy.
Worked example
Penicillin anaphylaxis is a type B (bizarre, immunological, not dose-related) reaction; bleeding on a high warfarin dose is type A.
In the exam
A patient develops anaphylaxis on first exposure to a drug at a normal dose — an unpredictable, non-dose-related reaction.
What settles it
Type A is predictable and dose-related (augmented pharmacology); type B is unpredictable and not dose-related (idiosyncratic/immune).
Classically confused with
CYP450 inhibitors
Source: Rawlins & Thompson; BNF