Long v short half-life benzodiazepines in the elderly. Kinetics and clinical effects of diazepam and oxazepam.

Oxazepam and diazepam were compared in healthy elderly volunteers. Absorption of diazepam was faster than oxazepam and onset of clinical effects were more profound. Diazepam accumulation was extensive, washout was slow and active compounds were present two weeks after the last dose. Oxazepam accumulation was significantly less and elimination significantly faster than diazepam. There was no difference between oxazepam and diazepam in sedation or fatigue during the drug treatment, but sedative effects persisted for two weeks after diazepam therapy was discontinued. Sedation rapidly returned to baseline in the oxazepam group. Thus, the differing pharmacokinetic profiles of diazepam and oxazepam have clinical consequences during multiple dosage in the elderly.