Clozapine treatment of schizophrenic patients. Plasma concentration and coagulation factors.

Eleven male, chronic schizophrenic, hospitalized patients, treated with a constant dose of clozapine (range 200-600 mg daily) as their only neuroleptic medication were studied for a long period of time (minimum 12 weeks). Wide variations in the plasma concentration of clozapine were found in different patients who received the same oral dose, as well as great changes from week to week in the individual patient given a constant dose. The plasma levels of clozapine appeared to have no correlation with either the clinical effect or the side effects. No differences with regard to coagulation factors were found between the patients and the controls.