Effects of anticonvulsants on acute cypermethrin poisoning in mice and rats

Male albino mice were given 35 mg cypermethrin/kg bw followed immediately by 1.0, 2.5 or 5 mg diazepam/kg, 5, 10 or 20 mg phenobarbitone/kg, or 10, 25 or 50 mg diphenylhydantoin/kg ip in dose groups of 10 mice each. Effectiveness of therapy was assessed by alleviation of effects and survival percentage. Rat brains implanted with electroencephalographic (EEG) and electromyograhic electrodes were given 58 mg cypermethrin/ kg followed by 5 mg diazepam/kg, 20 mg phenobarbitone/kg, or 50 mg diphenylhydantoin/kg. Diazepam at 5 mg or 20 mg phenobarbitone/kg produced 100% survival and alleviated all the signs of poisoning while diphenylhydantoin produced 80% survival at 50 mg/kg. The antidotes antagonised desynchronization of EEG waves produced in rats exposed to cypermethrin. These results suggest involvement of GABA in the mechanism of cypermethrin action in addition to its established effect on the sodium ion channel.