SEARCH FOR A THERAPEUTIC RANGE FOR SERUM ZUCLOPENTHIXOL CONCENTRATIONS IN SCHIZOPHRENIC-PATIENTS

The aim of our study was to find a therapeutic range for the serum con centration of zuclopenthixol (S-Zu) in chronic schizophrenic patients. S-Zu was measured in 17 patients and dosage reduction was suggested b y the laboratory if S-Zu exceeded 15 nmol/L. The clinical symptoms and side effects were evaluated blindly using the Brief Psychiatric Ratin g Scale (BPRS) and the UKU rating scale, respectively. S-Zu and rating s were repeated 6, 12, and 24 weeks after the final dosage adjustments . In 7 of 10 patients with S-Zu >15 nmol/L the dosage was reduced by 2 0-67%. After dosage reduction the S-Zu was below 15 nmol/L in 10 of th e 17 patients. The mean BPRS score and the side effects, evaluated by the UKU scale, were reduced in patients in whom the dosage was reduced . It is suggested that S-Zu in the range 5-15 nmol/L may serve as a pr eliminary therapeutic range for S-Zu.