Pazinaclone is a nonbenzodiazepine partial agonist. Animal work has shown that it has anxiolytic and anticonvulsant activity. Pazinaclone does not, however, produce the sedative, muscle relaxant, or motor coordination effects seen with diazepam (Waka and Fukada 1991). Phase II clinical trials are currently under way in the United States, Europe, and Japan, which have so far demonstrated that it is well tolerated and seems to cause significantly less sedation than do benzodiazepines (Uchiumi et al. 1992).
Pazinaclone is a sedative and anxiolytic drug in the cyclopyrrolone family of drugs. Other cyclopyrrolone drugs include zopiclone and eszopiclone. Pazinaclone has a very similar pharmacological profile to the benzodiazepine family of drugs including sedative and anxiolytic properties, but with less amnestic effects, and at low doses it is a relatively selective anxiolytic, with sedative effects only appearing at higher doses. Pazinaclone produces its sedative and anxiolytic effects by acting as a partial agonist at GABAA benzodiazepine receptors, although pazinaclone is more subtype-selective than most benzodiazepines.
