Lack of Correlation Between the Anaesthetic and Anti-Convulsant Potencies of Althesin, Ketamine and Methohexitone

Abstract

Using Sprague-Dawley rats, the anti-convulsant potencies of Althesin, ketamine and methohexitone were determined for bicuculline-and strychnine-induced seizures and compared with their effects on hyperbaric seizures. All three anaesthetics protected against both types of chemical convulsants; the degree of protection varied from 34 to 151%, with Althesin being the most effective. However, there was no correlation between their anti-convulsant and anaesthetic potencies, and no relationship between the effects on chemical convulsions and the interactions of the same agents with hyperbaric convulsions. These data suggest that the order of anti-convulsant potencies at equivalent anaesthetic concentration is Althesin much greater than ketamine = methohexitone, and that neither bicuculline-nor strychnine-induced seizures are a good model for hyperbaric convulsions.

Does Glycine Antagonism Underlie the Excitatory Effects of Methohexitone and Propofol

“…It is not certain if all these reports of tonic/clonic movements in man were true seizures because EEG documentation was generally unavailable. In addition, some anaesthetic drugs that produce CNS excitation also have anticonvulsant properties in some experimental models of epilepsy [3].…”