Correlation of Plasma Concentrations of Benzodiazepines with Clinical Effects

Abstract

Although this book is primarily concerned with sleep and hypnotics, I have widened the scope of this chapter to include anxiolytic uses of the benzodiazepines, otherwise my paper would have been even more devoid of firm data than it is already. There is, however, some logic in dealing with anxiety and sleep disorders together. Firstly, many, but by no means all, insomniacs have associated high levels of anxiety, and amelioration of the anxiety is conducive to sleep. Secondly, and arising partly from the first point, the use of benzodiazepines in the treatment of insomnia can be roughly divided into two strategies, each with the most appropriate choice of anxiolytic based on the relative pharmacokinetics of the various members of the class. The clinician can try a direct approach using a single large dose of a benzodiazepine as an hypnotic. The pharmacokinetic profile of an appropriate drug would be such as to provide: (a) a rapid and dependable onset of action; (b) a short duration of action (6–8 hours); (c) no appreciable active metabolites to prolong the action. The 3-hydroxy derivatives, temazepam and lorazepam, are examples of benzodiazepines approximating these criteria.