precipitating factors
Last reviewed 06/2022
The most common precipitants are drug ingestion, alcohol consumption, and endogenous and exogenous steroid hormonal factors.
AIP, VP and HCP may be precipitated by:
- alcohol
- 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
- infections
- starvation
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.