Metabolised by CYP 3A4. No data pointing to CYP-induction. Reported to have been used by some patients without porphyrinogenic side effects. Plasma concentrations probably below mmol range.

Cyclopyrrolone hypnotic (5-7.5 mg/d). Metabolized by hepatic CYP 3A4. South African list: no data/ avoid. Andersson; patient inquiry: used without illeffects (n=4). Thunell, patient inquiry: tolerated (n=1)

Uneventful use reported in 37 patients with acute porphyria.