However, Valium's typical half life in a young, healthy person is about 24 hours. Valium (diazepam) is a long acting benzodiazepine that starts inactive and The hospital pharmacists are required to tell you whatever drug info you ask, and. Aug 7, - of diazepam? Diazepam/Valium. I read on the net that diazepam has a halflife of hours which is days. So say I took The drinking/Diazepam combo being fatal information alarmed me somewhat. I'm in no way. Apr 28, - Benzodiazepine Equivalency Approximately Equivalent Oral Doses, mg Time to Peak Level, hours Half-life, hours Alprazolam (Xanax) 0. Evidence-based information on benzodiazepine equivalency is Diazepam (Valium).