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ABCDE: Augmented, Bizarre, Chronic, Delayed, End of treatment
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ABCDE:
- A - Augmented: an exaggeration of the drug’s known pharmacology. Dose related, predictable, common, low mortality. Bleeding on warfarin, hypoglycaemia on insulin, bradycardia on beta blockers. Manage by reducing the dose
- B - Bizarre: idiosyncratic, not dose related, unpredictable, rarer but higher mortality. Anaphylaxis, Stevens-Johnson syndrome, malignant hyperthermia, agranulocytosis with clozapine. Manage by stopping the drug
- C - Chronic: related to cumulative dose and duration. Steroid osteoporosis, analgesic nephropathy, amiodarone thyroid and lung toxicity
- D - Delayed: appearing long after exposure. Carcinogenesis, teratogenesis, tardive dyskinesia
- E - End of treatment: withdrawal phenomena. Rebound hypertension after clonidine, adrenal crisis after steroids, seizures after benzodiazepines
Type A accounts for about 80 per cent of reactions.
Reporting: suspected reactions should be reported through the Yellow Card scheme, particularly for newly licensed drugs marked with a black triangle, since rare type B reactions only emerge in post-marketing surveillance.