Cetirizine is a medication used for the treatment of allergies, hay fever, angioedema, and hives. It is a second-generation H1-receptor antagonist antihistamine and works by blocking H1 histamine receptors. It is a major metabolite of hydroxyzine, and has the same basic side effects, including dry mouth. A potent second-generation histamine H1 antagonist that is effective in the treatment of allergic rhinitis, chronic urticaria, and pollen-induced asthma. Unlike many traditional antihistamines, it does not cause drowsiness or anticholinergic side effects. Cetirizine hydrochloride is a medication used for the treatment of allergies, hay fever, angioedema, and hives. It is a second-generation H1-receptor antagonist antihistamine and works by blocking H1 histamine receptors. It is a major metabolite of hydroxyzine, and has the same basic side effects, including dry mouth.
Belongs to the class of organic compounds known as diphenylmethanes. Diphenylmethanes are compounds containing a diphenylmethane moiety, which consists of a methane wherein two hydrogen atoms are replaced by two phenyl groups.
Oral; mean peak plasma concentration (Cmax) of 114 ng/mL at a time (Tmax) of 2.2 hours postdose was observed for cetirizine.
Mechanism of Toxicity
Cetirizine competes with histamine for binding at H1-receptor sites on the effector cell surface, resulting in suppression of histaminic edema, flare, and pruritus. The low incidence of sedation can be attributed to reduced penetration of cetirizine into the CNS as a result of the less lipophilic carboxyl group on the ethylamine side chain.
No indication of carcinogenicity to humans (not listed by IARC).
Uses/Sources
For the relief of symptoms associated with seasonal allergic rhinitis, perennial allergic rhinitis and the treatment of the uncomplicated skin manifestations of chronic idiopathic urticaria
Minimum Risk Level
Not Available
Health Effects
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. (13)
Symptoms
Somnolence (sleepiness or unusual drowsiness), restlessness, irritability.
Treatment
Should overdose occur, treatment should be symptomatic or supportive, taking into account any concomitantly ingested medications. There is no known specific antidote to Cetirizine. (13)
Manne Reddy, “Polymorphic forms of dihydrochloride salts of cetirizine and processes for preparation thereof.” U.S. Patent US20040186112, issued September 23, 2004.
