Cetrizine-autocoids and its therapeutic uses

               

 CETRIZINE(trade names Zirtec, Zyrtec, Reactine) is a second-generation antihistamine used in the treatment of hay fever, allergies, angioedema, and urticaria.[1] It is a major metabolite of hydroxyzine, and a racemic selective H1 receptor antagonist.

Second-generation antihistamines like cetirizine are less able to cross the blood-brain barrier and therefore have diminished effects on the central nervous system compared to first-generation drugs: for instance they are less likely to induce drowsiness or to interfere with memory formation.

 

Mechanism of Actions:

Cetirizine, a human metabolite of hydroxyzine, is an antihistamine; its principal effects are mediated via selective inhibition of peripheral H1 receptors. The antihistaminic activity of cetirizine has been clearly documented in a variety of animal and human models. in vivo and ex vivo animal models have shown negligible anticholinergic and antiserotonergic activity. In clinical studies, however, dry mouth was more common with cetirizine than with placebo. In vitro receptor binding studies have shown no measurable affinity for other than H1 receptors. Autoradiographic studies with radiolabeled cetirizine in the rat have shown negligible penetration into the brain. Ex vivo experiments in the mouse have shown that systemically administered cetirizine does not significantly occupy cerebral H1 receptors.

 

 THERAPEUTIC Uses

1.Cetirizine is an antihistamine used to relieve allergy symptoms such as watery eyes,runny nose, itching eyes/nose, sneezing, hives, and itching.

2. chronic urticaria

3.Rhinovirus infection

4.Kimura's disease

5.Angioadema

 

Side effect

Commonly reported side effects of cetirizine include headache (16%), dry mouth (5.7%), and drowsiness (5-20%) or fatigue (5.6%).

 

DRUG-DRUG INTERACTION 

1.    Theophylline +citrizine=dacrease clearance of citrizine.

2.    pseudoephedrine, antipyrine, ketoconazole, erythromycin and azithromycin+ citrizine= no interaction

REFERENCE- Tripathi K.D. "Essentials of Medical Pharmacology", 7th Edition, page no- 164