The most common precipitants are drug ingestion, alcohol consumption, and endogenous and exogenous steroid hormonal factors.
AIP, VP and HCP may be precipitated by:
- drugs, especially barbiturates, and sulphonamides; enzyme inducing anticonvulsants, for example carbamazepine, phenytoin, phenobarbitone, primodone, oral contraceptive pill; also, diphenylhydantoin, rifampicin, chlordiazepoxide, griseofulvin and ergots.
- fluctuations in female sex hormones may also precipitate acute porphyrias
Clinical features are similar to those seen in lead poisoning (abdominal pain, constipation or vomiting, peripheral neuropathy, confusion or psychosis, tachycardia, hypertension).
For a comprehensive list of contraindicated drugs consult the British National Formulary.
Last reviewed 11/2021