Trihexyphenidyl (benzhexol) in clozapine-induced nocturnal enuresis and sialorrhea.

Sir, Clozapine is an atypical antipsychotic medication. It is the agent of choice to treat patients with schizophrenia who are treatment-resistant and who are prone to extrapyramidal symptoms. However, besides occasional serious and life-threatening side effects like agranulocytosis, myocarditis, and seizures, clozapine is often discontinued because of many common and troublesome side effects like sialorrhea, sedation, weight gain, and nocturnal enuresis in up to 17% of patients.[1] Clozapine-induced sialorrhea occurs at rates varying from 10 to 80% as reported in the literature.[2] Nocturnal enuresis is a less commonly reported side effect with a reported frequency varying from as little as 0.23% to as high as 41%.[3,4]