Acute intermittent porphyria

Attacks manifest as severe abdominal pain, vomiting, anxiety, confusion, autonomic instability, dehydration and electrolyte disturbances.

Progressive neuropathy is thought to be a consequence of direct ALA neurotoxicity or diminished intraneuronal heme.

Drug triggers

Thiopental

The majority of described drug-precipitated attacks have been associated with thiopental. Not every administration results in a porphyric crisis.

Benodiazepines

Diazepam has been implicated as a trigger, though it has also been used safely

Ketamine

Has been implicated as a trigger, though possibly only at high, supratherapeutic levels

Halothane

Historical reports of an association with halothane have not been borne out in clinical experience

Drugs with a history of safety in porphyria

• Propofol
• Suxamethonium
• Vecuronium, pancuronium
• Atracurium
• Bupivucaine
• Volatile anaesthetics (other than halothane)