3-Hydroxyphenazepam-d5 is a labelled analog of 3-hydroxyphenazepam. 3-Hydroxyphenazepam is a metabolite of Phenazepam (P295300), a benzodiazepine drug, which is used in the treatment of neurological disorders such as epilepsy, alcohol withdrawal and insomnia. It can be used as a premedication before surgery as it augments the effects of anesthetics and reduces anxiety.