Information about Cetirizine
Cetirizine and its enantiomer levocetirizine are second generation antihistamines that are used for the treatment of allergic rhinitis, angioedema and chronic urticaria.
Liver safety of Cetirizine
Cetirizine and levocetirizine have been linked to rare, isolated instances of clinically apparent acute liver injury.
Mechanism of action of Cetirizine
Cetirizine (se tir' i zeen) is a second generation antihistamine (H1 receptor blocker) that is used widely to treat allergic symptoms associated with hay fever, seasonal allergies, urticaria, angioedema and atopic dermatitis. Levocetirizine (lee" voe se tir' i zeen) is the levorotatory R-enantiomer of cetirizine and its more active form. Cetirizine and levocetirizine belong to the piperazine class of antihistamines and, like other second generation antihistamines, are considered to be nonsedating. Indeed, prospective studies have shown that sedation is less common with cetirizine and levocetirizine than with first generation antihistamines such as diphenhydramine, but some degree of sedation may still occur.
FDA approval information for Cetirizine
Cetirizine was approved for use by prescription in the United States in 1995 and as an over-the-counter medication in 2007. Cetirizine is currently one of the most widely used medications with more than 5 million prescriptions filled yearly in addition to considerable nonprescription use.
Dosage and administration for Cetirizine
Cetirizine is available in 5 and 10 mg tablets and capsules in multiple generic forms and under the trade name Zyrtec. Oral solutions and fixed combinations with pseudoephrine are also available. The typical dose of cetirizine is 5 to 10 mg once daily and it is often given chronically, at least during allergy season. Levocetirizine was approved for use in the United States in 2007 and is currently available by prescription only.
Brand name for Cetirizine
Levocetirizine is available in 5 mg tablets and in an oral solution generically and under the brand name Xyzal.
Side effects of Cetirizine
Common side effects of the second generation antihistamines include blurred vision, dry mouth and throat, palpitations, tachycardia, abdominal distress, constipation and headache. Although considered to be nonsedating antihistamines, cetirizine and levocetirizine can cause mild drowsiness particularly at higher doses. Antihistamines can worsen urinary retention and glaucoma.
First Generation Antihistamines
Second Generation Antihistamines