Differences in Diazepam and Oxazepam

To the Editor.—  In their article in the March 1983 Archives,¹ Salzman et al found no difference in sedation or fatigue effects in patients taking diazepam or oxazepam during two weeks of drug therapy. Although the authors noted a persistence of sedative effects from diazepam for a longer period of time after administration of both drugs was discontinued, the experimental design precluded a full elucidation of the differences in sedative effects of these two antianxiety agents. In addition, the pharmacokinetic and probable pharmacodynamic differences between these two drugs are often ignored when they are prescribed to elderly patients.The authors' findings were based on assessment of subjective effects obtained during two weeks of chronic diazepam and oxazepam therapy and kinetic data obtained over a longer washout interval. While the half-life of oxazepam averaged 10.7 hours (range, 5.0 to 19.4 hours), those of diazepam and its major active metabolite were