Pharmacokinetics of midazolam and alpha-hydroxy-midazolam following rectal and intravenous administration

Br J Clin Pharmacol. 1988 Apr;25(4):457-63. doi: 10.1111/j.1365-2125.1988.tb03330.x.


1. In an open cross-over trial, plasma concentrations of midazolam were measured in eight healthy male volunteers following administration of 0.3 mg kg-1 body weight given by the rectal and intravenous routes. 2. Maximum plasma concentrations of 92-156 ng ml-1 (mean 118 ng ml-1) were recorded from 20 to 50 min (mean 31 min) after rectal application. The rectal bioavailability was 40-65% (mean 52%) and the terminal half-life was 114-305 min (mean 161 min). 3. A substantial first-pass hepatic effect was observed following rectal administration. 4. No systemic or local intolerance was noted. 5. In conclusion, the rectal route of administration provides a rapid and reliable absorption of midazolam.

MeSH terms

  • Administration, Rectal
  • Adult
  • Biological Availability
  • Half-Life
  • Humans
  • Injections, Intravenous
  • Male
  • Midazolam / administration & dosage
  • Midazolam / analogs & derivatives*
  • Midazolam / pharmacokinetics*


  • 1-hydroxymethylmidazolam
  • Midazolam