Haloperidol decanoate in chronic schizophrenia: A study of 12 months with plasma levels

1. 1. Clinical activity, extrapyramidal side-effects were evaluated in 22 schizophrenic out patients diagnosed according to DSM III and treated with haioperidol decanoate (50–300 mg i.m. monthly dose) for 12 months. 2. 2. BPRS total scores did not show significant fluctuations showing a clinical stability of the patient population. 3. 3. Patients with a duration of illness > 10 yrs (Group 2) showed significant (p < 0.01) higher EPSE total scores compared to those with a duration of illness < 10 yrs (Group 1). 4. 4. A positive correlation was found between the administered dose and haloperidol plasma levels. 5. 5. Patients from Group 2 reached the steady-state more slowly and showed a lower total L/D ratio compared to those from Group 1. 6. 6. The pharmacokinetic approach seems desirable in order to adjust the dose and avoid schizophrenic relapses.