Induction of anaesthesia with etomidate in a patient with acute intermittent porphyria

This is a case report of a 35-year-old female with acute intermittent porphyria who presented for elective vagotomy and pyloroplasty. The diagnosis of porphyria was made two years previously when she developed acute abdominal pain and lower motor neurone paralysis following ingestion of a barbiturate. The urine porphobilinogen test was positive. The patient had no other acute attack of porphyria and had not had a previous anaesthetic. Anaesthesia was induced with etomidate 0.3 mg X kg-1 IV. Muscle relaxation was obtained with pancuronium 6 mg IV and ventilation was mechanically controlled. Intraoperative analgesia was with 66 per cent nitrous oxide in oxygen and intermittent doses of fentanyl. The patient was stable during anaesthesia and surgery. The postoperative period was uneventful and patient did not have an acute attack of porphyria. This experience suggests that etomidate is safe for intravenous induction of anaesthesia in acute intermittent porphyria. However, reports of its use in more patients with this disease will be necessary before a final conclusion can be made.