Influence of lansoprazole treatment on diazepam plasma concentrations

Clin Pharmacol Ther. 1992 Nov;52(5):458-63. doi: 10.1038/clpt.1992.172.


The possible influence of long-term treatment with lansoprazole on the single-dose pharmacokinetics of diazepam was investigated in 12 healthy male volunteers. In this double-blind randomized crossover study, 60 mg lansoprazole or placebo was administered once daily for 10 days. One hour after administration on day 7, 0.1 mg/kg diazepam was administered intravenously, and blood was collected up to 96 hours after the injection for plasma diazepam and desmethyldiazepam measurement. During the placebo session, the plasma elimination half-life, clearance, and volume of distribution of diazepam were 26.0 +/- 1.6 hours, 22.5 +/- 1.1 ml/hr/kg, and 0.82 +/- 0.04 L/kg, respectively. These parameters were not significantly different during the lansoprazole session. The mean plasma concentrations of desmethyldiazepam were similar in both sessions. These findings illustrate that long-term treatment with a therapeutic dose of lansoprazole does not interfere with the metabolism of diazepam.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2-Pyridinylmethylsulfinylbenzimidazoles
  • Adult
  • Analysis of Variance
  • Anti-Ulcer Agents / pharmacology*
  • Diazepam / blood
  • Diazepam / pharmacokinetics*
  • Double-Blind Method
  • Drug Interactions
  • Humans
  • Lansoprazole
  • Male
  • Omeprazole / analogs & derivatives*
  • Omeprazole / pharmacology
  • Reference Values


  • 2-Pyridinylmethylsulfinylbenzimidazoles
  • Anti-Ulcer Agents
  • Lansoprazole
  • Omeprazole
  • Diazepam