Factors associated with laxative use in schizophrenia patients treated with second-generation antipsychotics

The aim of this study was to investigate factors associated with concomitant laxative use among schizophrenia patients discharged on second-generation antipsychotics (SGAs) at two large psychiatric hospitals in Taiwan. Patients with schizophrenia who were discharged between 2006 and 2017 and received SGA monotherapy at discharge were included in the analysis. Multivariate logistic regression was used to identify factors associated with regular laxative use at discharge. Multivariate Cox regression was used to determine the effect of laxative use at discharge on time to rehospitalization within one year. The Cochran-Armitage trend test was used to evaluate whether significant time trends existed for rates of laxative use at discharge during the study period. Among patients discharged on SGAs (n = 11,861), 3,336 (28.1%) also received concomitant laxatives. Advanced age and higher antipsychotic or anticholinergic doses were found to be associated with an increase in laxative use. Among SGAs, clozapine was associated with the highest rate of laxative use, followed by zotepine, quetiapine, olanzapine and risperidone. Additionally, risperidone, amisulpride, aripiprazole, paliperidone and ziprasidone were associated with comparable rates of laxative use. In contrast, sulpiride was least associated with laxative use among all SGAs. Regular laxative use at discharge was found to be significantly associated with psychiatric rehospitalization. Also, rate of laxative use at discharge increased significantly during the study period. Laxative use is common in schizophrenia patients treated with SGAs. For clinically significant constipation, switching to an SGA with a lower risk for constipation, and decreasing the doses of SGAs and anticholinergics should be considered.