Metabolised by CYP 3A4 but no clinical data pointing to CYP-induction. Two references stating non-porphyrinogenicity.

Selective 5-HT-antagonist used as antiemetic for postoperative nausea and nausea under chemotherapy, 4-32 mg/d given perorally or intravenously. Hydroxylated and conjugated to glucuronic acid and sulfate via CYP 3A4. No instances for clinically significant CYP- induction observed. MFM James, RJ Hift. Porphyrias. Br J Anaesth 2000; 85, 143-53: use with care South African list: use with care. French list: authorized

Uneventful use reported in 12 patients with acute porphyria.