Cis(Z)-clopenthixol and clopenthixol (Sordinol) in chronic psychotic patients. A double-blind clinical investigation.

The clinical effect of cis(Z)-clopenthixol has been compared with that of clopenthixol, which is a mixture of the pharmacologically active cis(Z)-isomer and the inactive trans(E)-isomer. In the 2-month double-blind trial were included 57 psychotic patients, mainly schizophrenics. Ratings evaluating severity of illness, therapeutic effect, possible interference of side effects with the patient's functioning, as well as any individual side effects were done at months 0, 1, and 2. The antipsychotic effect of cis(Z)-clopenthixol was found equal to that of clopenthixol whereas the cis(Z)-isomer on a mg/mg basis was twice as active as clopenthixol. Apart from the finding that the unspecific sedative effect appeared to be less marked with cis(Z)-clopenthixol, the type, degree, and frequency of side effects were the same in the two groups of patients. More than half of the patients experienced no side effects.