An antagonist-induced benzodiazepine abstinence syndrome.

Cats were treated for 35 days with flurazepam, 5 mg/kg per day. The drug was administered through a gastric fistula. Ro15-1788, a benzodiazepine antagonist, caused an abstinence syndrome when administered through the gastric fistula 24 h after the last dose of chronic treatment. Abstinence signs included increased muscle tone, tremor, piloerection, pupillary dilation, panting, and excessive salivation. Neither convulsions nor delirium was seen. Severity of abstinence was similar after Ro15-1788 doses of 2-100 mg/kg, but lasted longer (8-10 h) after the higher dose. Readministering Ro15-1788 a week after the end of chronic treatment precipitated an attenuated abstinence syndrome, but was inactive after 2 weeks.