[Zopiclone. Data of experimental pharmacology and clinical use]

Zopiclone is the first of the cyclopyrrolones, a new class of psychotropic agents which is chemically different from the benzodiazepines (BZD). From an experimental point of view it has qualitatively the pharmacological profile of the tranquilizer-hyponotics, and activity quantitatively differs from hypnotic BZD by its lower myorelaxant. The electroencephalographic studies also demonstrated that its power spectrum is characteristic of a product having a tranquilizing hypnotic potential. The cyclopyrrolones interact with GABA ergic neurotransmission, and have a high affinity for GABA receptor complex. They act on sites close to BZD sites, but physically different. The sleep polygraphic studies have shown that zopiclone has a specific profile. It respects the sleep architecture, specially the delta sleep which is even increased, in some studies. Its residual effects are absent or minimal, and its acceptability is good in the usual conditions of hypnotic prescription.