Therapeutic Effects of Methocarbamol on Acute Intoxication by Pyrethroids in Rats

Abstract

The therapeutic potency of intraperitoneally administered methocarbamol was examined against acute oral intoxication of rats caused by lethal doses of pyrethroids (fenvalerate, cypermethrin, fenpropathrin and permethrin). Methocarbamol was initially administered a dose of 400 mg/kg (body weight), followed by repeated doses of 200 mg/kg, when tremors or hyperexcitability to sound was observed. Methocarbamol markedly decreased the mortality; 80% mortality caused by an administration of 850 mg/kg (body weight) fenvalerate to 0%, 80% mortality by 850 mg/kg cypermethrin to 0%, 60% mortality by 100 mg/kg fenpropathrin to 0% and 70% mortality by 850 mg/kg permethrin to 10%, and it was effec-tive in alleviating motor symptoms such as fibrillation, tremors, hyperexcitability, clonic seizures and/or choreoathetotic movements. A subcutaneous administration of 25 mg/kg (body weight) atropine sulfate was also effective in mitigating salivation produced by fenvalerate and cypermethrin. © 1986, Pesticide Science Society of Japan. All rights reserved.