Acute intermittent porphyria is an inherited disease: the body lacks an enzyme that is used to make hemoglobin out of molecules, called porphyrins. Porphyrins build up in the body when they are not used to make hemoglobin. High levels of porphyrins are toxic to the brain, nerves, skin and gastrointestinal tract. The illness can result in attacks of symptoms that may last for days to weeks.

Attacks of acute intermittent porphyria can be caused by:

• Sun exposure
• Medications:
• Alcohol
• Barbiturates
• Carbamazepine
• Chlorpropamide
• Danazol
• Ergots
• Estrogen
• Ethchlorvynol
• Glutethimide
• Griseofulvin
• Mephenytoin
• Meprobamate
• Methotrexate
• Methyprylon
• Phenytoin
• Sulfa drugs
• Valproic acid