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Overdosage has been reported with ZYRTEC (cetirizine) . In one adult patient who took 150 mg of ZYRTEC (cetirizine) , the patient was somnolent but did not display any other clinical signs or abnormal blood chemistry or hematology results. In an 18 month old pediatric patient who took an overdose of ZYRTEC (cetirizine) (approximately 180 mg), restlessness and irritability were observed initially; this was followed by drowsiness. Should overdose occur, treatment should be symptomatic or supportive, taking into account any concomitantly ingested medications. There is no known specific antidote to ZYRTEC (cetirizine) . ZYRTEC (cetirizine) is not effectively removed by dialysis, and dialysis will be ineffective unless a dialyzable agent has been concomitantly ingested. The acute minimal lethal oral doses were 237 mg/kg in mice (approximately 95 times the maximum recommended daily oral dose in adults on a mg/m² basis, or approximately 40 times the maximum recommended daily oral dose in infants on a mg/m² basis) and 562 mg/kg in rats (approximately 460 times the maximum recommended daily oral dose in adults on a mg/m² basis, or approximately 190 times the maximum recommended daily oral dose in infants on a mg/m² basis). In rodents, the target of acute toxicity was the central nervous system, and the target of multiple-dose toxicity was the liver.

ZYRTEC (cetirizine) is contraindicated in those patients with a known hypersensitivity to it or any of its ingredients or hydroxyzine.

Last reviewed on RxList: 5/17/2007
This monograph has been modified to include the generic and brand name in many instances.