Dosage patterns of antipsychotic drugs for the treatment of schizophrenia in Swedish ambulatory clinical practice--a highly individualized therapy.

Objective: To analyse the dosage pattern of antipsychotic drugs for schizophrenia in ambulatory care in Sweden.

Method: The study was based on a nationwide consecutive weekly random sample of physicians during the period 1991-98 comprising 265,331 visits.

Results: In 515 visits (0.19%), antipsychotics were prescribed for schizophrenia. More than one antipsychotic (50 different combinations) was prescribed in 20% of the visits. Patients received higher total daily doses when prescribed more than one antipsychotic drug; mean dose in monotherapy was 210.7 chlorpromazine equivalents (CPZeq) and in polytherapy 406.8 CPZeq.

Conclusion: Antipsychotics, in contrast to current recommendations, were prescribed as highly individualized therapies in a wide variety of doses and with a high frequency of polypharmacy. The combinations used are often unsuitable and may lead to unnecessary adverse effects.