Serum concentrations and clinical effect of zuclopenthixol in acutely disturbed, psychotic patients treated with zuclopenthixol acetate in Viscoleo.

Zuclopenthixol acetate, 5%, in Viscoleo was administered IM to 19 acutely disturbed, psychotic patients in doses of 50-150 mg. Fifteen patients received one injection, whereas four of the patients had two or three injections, usually with intervals of 3 days. The zuclopenthixol concentrations in serum were measured in series of samples taken from each patient during a 3-day period following the injection. In patients given identical doses serum concentrations of about the same order were obtained. Significant and good correlations were found between dose and maximal serum concentration and between dose and area under the serum concentration curve. The average serum concentration curve obtained when adjusting the data to a 100 mg dose has a maximum of 41 ng/ml after about 36 h, decreasing to 15 ng/ml after 72 h. A dose of 50-150 mg zuclopenthixol acetate in Viscoleo appeared to be sufficient for controlling the symptoms for most acutely disturbed, psychotic patients. The frequency of side effects, including extrapyramidal reactions, was low and the adverse reactions mostly mild, indicating that the risks for severe complications generally might be minimal. With a rapid onset of action, few and mild side effects, good tolerability at the injection site, and a duration of effect of 2-3 days, zuclopenthixol acetate in Viscoleo appears to offer advantages compared to conventional neuroleptic treatment in patients in whom an acute, calming effect is desired.