Trihexyphenidyl as a possible therapeutic option in clozapine-induced nocturnal enuresis.

Enuresis is an adverse event of clozapine treatment. The occurrence of nocturnal functional enuresis in two schizophrenic patients during the initial phase of clozapine therapy is reported. Beneficial effect of trihexyphenidyl administration (5 mg at 21.00 h) on clozapine-induced enuresis is clearly demonstrated in one patient. Trihexyphenidyl discontinuation and subsequent readministration in this patient led to corresponding recurrence and then disappearance of enuresis. Involvement of the cholinergic system has been proposed as one of the possible pathophysiological mechanisms of clozapine-induced enuresis.