Clozapine-treated patients are at significant risk for ileus primarily due to its potent anticholinergic properties. While the average colonic transit time in adults is 24 hours, for clozapine-treated patients not on laxatives the median CTT is over 4 times longer (110 hours). Even with use of maximal doses of each of the 3 common classes of laxatives (docusate; osmotic; stimulant) the median CTT remains elevated at 62 hours. Other anticholinergic medications, especially in cases of anticholinergic polypharmacy may produce adverse effects similar to clozapine.
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