Drug Interactions between clozapine and Snooze Fast

MONITOR CLOSELY: Concomitant use of clozapine with drugs that have anticholinergic properties (e.g., sedating antihistamines; antispasmodics; neuroleptics; phenothiazines; skeletal muscle relaxants; tricyclic antidepressants; disopyramide) may increase the risk for anticholinergic toxicity or severe gastrointestinal adverse reactions related to hypomotility. Clozapine alone can cause life-threatening gastrointestinal adverse effects in association with its potent anticholinergic activity, ranging from constipation to paralytic ileus. Excessive parasympatholytic effects may also result in hyperthermia, heat stroke, and the anticholinergic intoxication syndrome. Peripheral symptoms of intoxication commonly include mydriasis, blurred vision, flushed face, fever, dry skin and mucous membranes, tachycardia, urinary retention, and constipation. Central nervous system-depressant effects may also be additively or synergistically increased when these agents are combined, especially in elderly or debilitated patients. Use of clozapine in combination with other neuroleptics or anticholinergic agents may also increase the risk of tardive dyskinesia.

MANAGEMENT: Close monitoring for signs and symptoms of additive anticholinergic effects such as gastrointestinal hypomotility is advised when clozapine is used with other drugs that have anticholinergic properties, particularly in the elderly and those with underlying organic brain disease, who tend to be more sensitive to the central anticholinergic effects of these drugs and in whom toxicity symptoms may be easily overlooked. Some authorities recommend avoiding this combination. Patients should be advised to notify their physician promptly if they experience constipation or symptoms of anticholinergic intoxication such as abdominal pain, fever, heat intolerance, blurred vision, confusion, and/or hallucinations. Prompt treatment with appropriate laxatives and other measures are essential to minimize the risk of complications. Ambulatory patients should be counseled to avoid activities requiring mental alertness until they know how these agents affect them.