It has long been known that long-term phenothiazine therapy can produce paralytic ileus, obstruction, obstipation, and constipation. It is hypothesized that this is mediated by phenothiazines' parasympatholytic action on the gastrointestinal tract. However, in animal models, potent anticholinergic action alone is not sufficient to account for the tissue damage (inflammation, edema, and hemorrhage) produced by phenothiazines.1
Clozapine, an atypical neuroleptic medication with potent anticholinergic properties, is known to produce constipation in approximately 14% of patients. As of September 1, 1992, there have been at least 19 cases of severe complications of constipation associated with clozapine therapy (M. B. Krassner, MD, written communication, 1993). These included eight cases of bowel obstruction, seven cases of fecal impaction, three cases of paralytic ileus, and one case of obstipation. Several of these patients required hospitalization, four required surgical intervention, and in four cases, the outcome was fatal. Of the four patients who required surgical