Pharmacology of cis (Z) ‐ Clopenthixol Decanoate, a Depot Neuroleptic

The duration and intensity of the neuroleptic effect of cis(Z)‐clopenthixol decanoate in Viscoleo$rG have been compared with those of cis(Z)‐clopenthixol, 2 HCl in aqueous solution in a number of animal experimental models. Cis(Z)‐clopenthixol, 2 HCl had a strong, but short‐lasting neuroleptic effect (apomorphine antagonistic effect in dogs, inhibition of conditioned avoidance response in rats) which was accompanied by marked sedation. In contrast, cis(Z)‐clopenthixol decanoate in oil had an effect which was slower in onset, but of much longer duration and only the highest doses caused a slight sedation. In rats catalepsy could be induced in some animals by high doses of cis(Z)‐clopenthixol decanoate whereas cis(Z)‐clopenthixol, 2 HCl at all the doses tested caused catalepsy in all animals. In mice only high doses of cis(Z)‐clopenthixol decanoate in oil caused reduction of spontaneous motor activity and potentiation of barbiturate anaesthesia. The results are discussed with special reference to the clinical use of the depot preparation.