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Phenobarbitone can precipitate acute intermittent porphyria (AIP)

• by inducing cytochrome P450 enzymes it increasing heme synthesis, and accumulating toxic precursors (ALA and PBG).
• This triggers acute attacks with severe abdominal pain, neuropsychiatric symptoms, autonomic dysfunction, and muscle weakness.
• Other porphyrinogenic drugs (phenytoin, carbamazepine, valproate) should also be avoided.
• Safe alternatives include benzodiazepines (lorazepam, diazepam) for seizures and gabapentin for neuropathic pain.
• Diagnosis is confirmed by increased urinary PBG.
• Treatment includes glucose, hemin, and avoiding triggers.