Zyrtec Contraindications and Precautions
- breast-feeding
- hydroxyzine hypersensitivity
- dialysis
- driving or operating machinery
- elderly
- ethanol intoxication
- hepatic disease
- infants
- pregnancy
- renal failure
- renal impairment
Cetirizine Contraindications and Precautions
Cetirizine is contraindicated for use in patients with a known hypersensitivity to the drug or to any of the formulation components or who have known hydroxyzine hypersensitivity. Cetirizine is a known human metabolite of hydroxyzine.
Cetirizine has less affinity than some H1-blockers for calcium channel, alpha-adrenergic, D2-dopamine, 5HT2-serotonin and muscarinic receptors. A reduction in anticholinergic effects may mean that some of the restrictions to the use of older H1-blockers may not apply to cetirizine.
In clinical trials, drowsiness has been reported in some patients taking cetirizine; therefore patients receiving cetirizine should be advised to avoid driving or operating machinery until the effects of the drug are known. Because the effects of ethanol or other CNS depressants may be additive with antihistamines, ethanol intoxication should be avoided.
No overall differences in safety were observed between geriatric adults and young adults in clinical trials of cetirizine. A decline in renal function in the elderly (mean age 77 years) was responsible for prolonged half-life of cetirizine and reduced total clearance. Dosage adjustment is recommended for elderly patients >= 77 years (see Dosage). Similarly, in patients with moderate to severe renal impairment (CrCl <= 31 ml/min) or renal failure, a prolonged half-life and reduced clearance occurs. Cetirizine is not appreciably removed during dialysis. Dosage reduction is recommended in patient populations with reduced renal function.
Serum concentrations of cetirizine are greater in hepatically impaired patients and the drug clearance rate is reduced. Dosage adjustments are suggested for those with hepatic disease.
Cetirizine is classified in FDA pregnancy risk category B. Animal studies do not reveal a risk for teratogenesis, even at doses greatly exceeding the maximum recommended daily human dose on a mg/m2 basis. There have been no published reports on the use of cetirizine in human pregnancy, and animal studies are not always predictive of human response. Use during pregnancy only when the benefit outweighs the potential for fetal risk.
Cetirizine is excreted in human breast milk, but quantitative amounts are not known. In dogs, up to 3% of the dose is excreted in milk. In mice, cetirizine retarded pup weight gain at doses exceeding the maximum recommended daily human dose on a mg/m2 basis. Because there is a lack of information on safety during lactation, the manufacturer recommends against the use of cetirizine during breast-feeding.
The safety and efficacy of cetirizine have not been established in infants < 6 months of age.
[ Last revised: 5/31/2004 4:31:00 PM ]
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