A comparison of anticholinergic use by schizophrenic patients on polypharmacy and those receiving monotherapy

Abstract

Introduction: Schizophrenia is one of the most debilitating mental disorders globally and one of the most challenging illnesses to treat. Although guidelines consistently caution against antipsychotic polypharmacy (APP) in clinical practice, their prescription rate is still significant and leads to a greater side-effect burden in patients. Therefore, this study aimed to document the prevalence of APP-related anticholinergic use compared to monotherapy in patients with schizophrenia in the community psychiatric clinics in Soweto, Johannesburg. Methods: A retrospective record review was conducted. Data from clinical files of patients (18 years and above) diagnosed with schizophrenia attending four clinics in Soweto in September was analysed. Information such as age, gender, presence of extrapyramidal side-effects (EPSEs), comorbid conditions, and current treatment records was collected. Logistic regression assessed the association between APP, anticholinergic use, and sociodemographic and clinical characteristics. Results: One hundred files that met the inclusion criteria were reviewed. The study population consisted mainly of males (n=73, 73%), with an average age of 47.6 years and an average illness duration of 18.5 years. Of the 100 selected patients with schizophrenia, 35% were on APP, and 57.7% of those were prescribed an anticholinergic agent. Of the patients on anticholinergic agents, 92% had a prescription for a single first-generation antipsychotic (FGA) or an FGA in combination with a second-generation antipsychotic (SGA). The most prescribed antipsychotics were risperidone and flupenthixol decanoate, either as monotherapy or combined. Conclusion: The findings in this study correlated with the existing literature. Anticholinergic prescription rates are still high and associated with APP, male gender, and the use of FGAs.