Fluoxetine Benzatropine

An 11-year-old boy developed acute dysuria and increased frequency accompanied by gross hematuria. He was taking fluoxetine, valproic acid, benzatropine, haloperidol, clonidine, trazodone, and nasal desmopressin. One week before presentation, risperidone had been introduced instead of haloperidol to improve behavioral control. The risperidone was discontinued and haloperidol resumed, and his symptoms resolved during the following week. 

An 11-year-old boy developed acute dysuria and increased frequency accompanied by gross hematuria. He was taking fluoxetine, valproic acid, benzatropine. 

Eight patients deveioped deiirium when given fluoxetine, paroxetine or sertraline with benzatropine, in the presence of an antipsychotic (usually perphenazine or haloperidol). Other patients taking the combination remained symptom free. 

In contrast, another report describes 12 patients on fluoxetine and perphenazine who also received benzatropine 1 mg daily without showing signs of delirium. The general clinicd importance of this interaction is therefore very uncertain indeed, but it would now seem prudent to be alert for evidence of confusion and possible delirium in patients given SSRIs with benzatropine, particularly if they are also taking other psychotropics that may have antimuscarinic actions. The authors of the first report say that they have not seen delirium with combinations of SSRIs (not named) and other antimuscarinic drugs such as biperiden and diphenhydramine. ... 

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