Extra‐hepatic metabolism of midazolam.

Abstract

Six patients received 10 mg of midazolam intravenously during the anhepatic period of liver transplantation. Arterial blood was sampled during this time and for a similar period following revascularisation. The plasma was analysed using gas chromatography and electron capture detection (GC‐ECD) for midazolam alpha‐hydroxymidazolam and alpha‐ hydroxymidazolam glucuronide. Five of the six patients had small but significant concentrations of metabolites detected during the anhepatic period, demonstrating the presence of extra‐hepatic sites of metabolism for this drug. The remaining patient had plasma concentrations of metabolites below the lower limit of detection (2 micrograms l‐1). This may represent a pharmacogenetic abnormality or a temporary failure of midazolam metabolism secondary to the patients illness affecting the extra‐hepatic sites of metabolism. 1989 The British Pharmacological Society