Clozapine prescribing patterns in hospitalised patients in everyday clinical practice

Aim: Clozapine is the gold standard for treatment-resistant schizophrenia. Despite clear recommendations for use, under-use and excessive delay in the use of clozapine are an ongoing findings in the literature. The aim of this study was to analyse the clozapine prescribing patterns in hospitalised patients in everyday clinical practice in Serbia. Methods: This cross-sectional study was conducted in Clinic for Mental Disorders “'Dr Laza Lazarević”' in Belgrade and included a sample of 238 patients, discharged from hospital treatment during 2018. Demographic, data on the clinical characteristics of the subjects, dosage and combination of clozapine with other psychopharmacs were collected retrospectively, from the patients' medical records. Descriptive and statistical hypothesis testing methods were used to analyse the primary data. Results: The incidence of clozapine administration was 23.5%. Clozapine was introduced into therapy after average treatment duration of 7.2 years and prior administration of three different antipsychotics. 68.1% of patients were treated with dual antipsychotic therapy prior to clozapine administration. In 53.8% of patients, clozapine was prescribed as antipsychotic monotherapy, while only eight per cent were not prescribed adjuvant therapy. The most commonly used antipsychotic in combination with clozapine was haloperidol (34.9%), while the most prescribed non-antipsychotic adjuvant drug was valproate (66%). Benzodiazepines were prescribed in 55.9% of subjects. In most subjects, the dose of clozapine was less than the standard dose. Conclusion: Clozapine is prescribed less frequently than expected and is often used in an irrational manner. Additional research is needed to advance its application in everyday clinical practice.