Pyrazolopyrimidines.

Pharmacological therapy has an important role in the management of insomnia. Although older drugs are highly effective for initiating and maintaining sleep, tolerance and withdrawal effects as well as impairment of daytime performance are commonly troublesome and limit their use. Aided by increased knowledge of gamma-aminobutyric acid (GABA) and its receptors, new hypnotic sedatives have been developed that are increasingly selective for the various subunits of the GABA receptor. This development has produced newer agents with very favourable hypnotic profiles and side-effect profiles that provide better treatment options for medical practitioners. The pyrazolopyrimidines, the latest in this area, seem to offer some advantages over other agents.