Kinetics of high-dose i.v. diazepam

Area of Science:

• Pharmacology
• Intensive Care Medicine
• Clinical Pharmacokinetics

Background:

• Investigating the pharmacokinetic profile of high-dose intravenous diazepam in critically ill patients is crucial for optimizing therapeutic strategies.
• Understanding drug metabolism and elimination in the intensive care unit (ICU) setting is complex due to patient comorbidities and polypharmacy.

Observation:

• Two intensive care unit patients received high-dose intravenous diazepam (240 mg/day for 21 days and 60 mg/day for 30 days).
• Plasma concentrations of diazepam and its primary metabolite, desmethyldiazepam, were measured.
• Patients had severe underlying diseases and were administered multiple concomitant medications.

Findings:

• Despite high dosages and critical illness, the elimination half-lives of diazepam and desmethyldiazepam were comparable to those observed in healthy subjects.
• In one patient, washout half-lives appeared shorter than anticipated, potentially influenced by concurrent phenobarbitone administration.
• The pharmacokinetics of diazepam do not appear to be significantly altered by the administration of large doses in this context.

Implications:

• High-dose intravenous diazepam can be administered to ICU patients without expecting significant alterations in its pharmacokinetic profile.
• These findings support the continued use of diazepam in critical care settings for managing conditions requiring sedation or anxiolysis.
• Further research may explore the specific impact of phenobarbitone on diazepam washout kinetics in critically ill populations.