The porphyrias are a group of rare genetic disorders characterised by faults deficiency in any of the enzymes of the haem biosynthesis pathway which leads to haem precursor and (porphyrin) accumulation. The conditions are broadly categorised into acute and cutaneous (non-acute) porphyrias.

In the acute forms of porphyria (acute intermittent porphyria, aminolevulinate dehydratase deficiency porphyria, hereditary coproporphyria, variegate porphyria) some medicines can precipitate a painful acute attack. Acute attacks may be precipitated by drugs, alcohol, dieting, stress, infections, viruses and hormonal fluctuations, for this reason medication must be chosen carefully for patients with acute porphyrias.

Most medicines are safe in the cutaneous  porphyrias (congenital erythropoietic porphyria, erythropoietic protoporphyria or porphyria cutanea tarda) but there are some exceptions.

In addition to the articles below the UK Porphyria Medicines Information Service (UKPMIS) provides an advisory service on making safe medicine choices for people with porphyria. This service is available to UK healthcare professionals and people with porphyria living in the UK.