Drug Interactions between clozapine and Hycodan

GENERALLY AVOID: Concomitant use of opioids with central nervous system (CNS) depressants (e.g., benzodiazepines, sedatives/hypnotics, anxiolytics, muscle relaxants, general anesthetics, antipsychotics, other opioids, alcohol) may result in profound sedation, respiratory depression, coma, and death. The risk of hypotension may also be increased with some CNS depressants (e.g., alcohol, benzodiazepines, antipsychotics).

MANAGEMENT: The use of opioids in conjunction with benzodiazepines or other CNS depressants should generally be avoided unless alternative treatment options are inadequate. If coadministration is necessary, the dosage and duration of each drug should be limited to the minimum required to achieve desired clinical effect, with cautious titration and dosage adjustments when needed. Patients should be monitored closely for signs and symptoms of respiratory depression and sedation, and advised to avoid driving or operating hazardous machinery until they know how these medications affect them. Cough medications containing opioids (e.g., codeine, hydrocodone) should not be prescribed to patients using benzodiazepines or other CNS depressants including alcohol. For patients who have been receiving extended therapy with both an opioid and a benzodiazepine or antipsychotic and require discontinuation of either medication, a gradual tapering of dose is advised, since abrupt withdrawal may lead to withdrawal symptoms.

MONITOR CLOSELY: Concomitant use of some antipsychotics with other agents that can reduce gastrointestinal motility, such as opioids, may increase the risk of ileus and constipation. Certain antipsychotic agents, including phenothiazines, thioxanthenes, clozapine, olanzapine and quetiapine, can cause gastrointestinal adverse effects in association with their anticholinergic activity. Potential complications may include paralytic ileus, intestinal obstruction, fecal impaction, megacolon, and intestinal ischemia or infarction, particularly with agents that have potent anticholinergic effects such as clozapine and quetiapine.

MANAGEMENT: Close monitoring of bowel function is recommended during concomitant use of opioids with antipsychotic agents that exhibit anticholinergic effects, particularly in the elderly. Delayed diagnosis and treatment of constipation may increase the risk of severe complications, which can result in hospitalization, surgery, and death. Patients should be advised to maintain adequate hydration, physical activity and fiber intake, and to report any changes in the frequency or character of bowel movements as well as signs and symptoms of potential complications of ileus such as nausea, vomiting, abdominal distension, and abdominal pain. If constipation or gastrointestinal hypomotility is identified, monitor closely and treat promptly with appropriate laxatives to prevent severe complications. Consider prophylactic laxatives in high risk patients, such as those with a history of constipation, colonic disease, or lower abdominal surgery.

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.

MONITOR: Coadministration of opioids with anticholinergic agents may result in additive central nervous system (CNS), gastrointestinal, and genitourinary effects. The risk and/or severity of adverse effects such as sedation, dizziness, confusion, cognitive and psychomotor impairment, dry mouth, constipation, and urinary retention may increase. Severe constipation may lead to paralytic ileus in some cases.

MANAGEMENT: Caution and close monitoring of central nervous system, gastrointestinal, and genitourinary adverse effects are recommended when opioids are used with anticholinergic agents. Ambulatory patients should be counseled to avoid hazardous activities requiring mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.