Necurotoxic effect of intrathecal ketamine HCl: an experimental study in rabbits

ABSTRACT

Ketamine hydrochloride was injected intrathecally to study the possible acute and delayed neurotoxic effects in rabbits. In a dose of 2 mg.Kg-I b.wt., ketamine could produce analgesia to 70% of rabbits as manifested by hindpaw-pinch test and hot-plate test. No motor involvement nor behavioral changes were reported. Ketamine in a dose of 5 mg.kg-I b.w.t. Could produce analgesia in 100% of the animals, motor dysfunction and behavioral changes in the form of excitation and confusion followed by catalepsy. Histopathologically, oedema of the nerve cells was the general acute finding, being more marked in the high-dose group. The delayed effect of the drug was in the form of demyelination of the neurones. Also, the reaction was more marked in the high-dose group with chromatolysis of the cells and vascular proliferation. From the study, it was concluded that intrathecal ketamine HCI in rabbits caused neurotoxic effects in a dose-related manner, while behavioral changes were observed only under high dosage of the drug