Anticholinergic side effects

Abstract

Dear Editor, Antipsychotic drugs have efficacy in the treatment of psychosis. They are used as first-line medication treatment for schizophrenia. However, antipsychotic drugs have significant side effects. They can potentially cause extrapyramidal symptoms, orthostatic hypoten-sion, sedation, and anticholinergic effects. Anticholi-nergic side effects include urinary retention, constipa-tion, and dry mouth. 1 We here report the case of a schizophrenic patient who developed anticholinergic side effects from antipsychotic drugs. A 55-year-old man presented with abdominal disten-sion. There was a past history of schizophrenia. He was being treated with 25 mg/day of levomepromazine, 37.5 mg/day of chlorpromazine, and several types of psychotropic drugs due to his mental state being unstable. The abdomen showed a marked generalized distention and the bowel sounds were hypoactive. A computed tomographic scan of the abdominal pelvis showed a distended urinary bladder, bilateral hydro-nephrosis, and a distended colon (Figure 1). There were no obvious signs of a urinary obstruction or a bowel obstruction. A urethral catheter was inserted yielding 2000 ml of clear urine. He passed gas and stool with the aid of several different types of laxa-tives. In addition to these symptoms, excessive water consumption (5000 ml/day) was observed during his clinical course. Laboratory tests showed hyponatremia at Na 125 mmol/L, K 4.1 mmol/L, and Cl 88 mmol/L. Typical antipsychotics are commonly classified on a spectrum of low-potency to high-potency. Low-potency phenothiazines, such as levomepromazine and chlorpromazine, have a greater degree of anti-cholinergic side effects than high-potency butyrophe-nones. In contrast, atypical antipsychotics, such as quetiapine, have minimal intrinsic anticholinergic properties. 2,3 Therefore, chlorpromazine was discon-tinued, and quetiapine was administered. Silodosin and distigmine bromide were also administered for the treatment of neurogenic bladder. The therapy gradually improved the clinical symptoms of urinary retention, constipation, and dry mouth. We concluded that his clinical symptoms were mainly attributed to anticho-linergic effects from levomepromazine and chlorpro-mazine. His clinical symptoms could also have been induced by the interaction of many psychotropic drugs. As for his excessive water consumption, it was not solely due to drug-induced dry mouth. A previous study has shown that excessive water consumption is commonly associated with schizophrenic patients. 4 It is notable that the majority of these patients are not fully aware of the severity and possible complications.