Article: Cetirizine

Cetirizine
Systematic (IUPAC) name
2-[2-[4-[(4-chlorophenyl)-phenyl-methyl] piperazin-1-yl]ethoxy]acetic acid
Identifiers
CAS number	83881-51-0
ATC code	R06AE07
PubChem	2678
DrugBank	APRD00630
Chemical data
Formula	C21H25N2ClO3
Mol. weight	388.888
Pharmacokinetic data
Bioavailability	?
Metabolism	CYP3A4
Half life	8.3 Hours
Excretion	Hepatic
Therapeutic considerations
Pregnancy cat.	?
Legal status	Rx-only, OTC in Canada and UK
Routes	Oral

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.

• It has long duration of action
• No reported cardiotoxicity associated with the use of this drug
• Minimal penetration of the blood-brain barrier
• Only mild sedating effects, although more than some other non-sedating antihistamines

Brand Names

The medication is produced by UCB, a Belgian pharmaceutical company. The drug is marketed under the following brand names:

• Zyrtec in the USA
• Zirtek, Zynor and generically in the United Kingdom
• Zyrlex in many other European countries
• Reactine in Canada (as well as generically) and Europe (all by Pfizer [1])
• Benaday and generic Cetirizin in Denmark
• Virlix in Mexico and parts of Europe (by GlaxoSmithKline [2])
• Humex in France

It can be found under a variety of other brand names in other countries [3].

Formulations

Like many other antihistamine medications, cetirizine is commonly prescribed in combination with pseudoephedrine hydrochloride, a decongestant. These combinations are marketed using the same brand name as the cetirizine with a "-D" suffix (Zyrtec-D, Virlix-D, etc.)