Perennial allergic rhinitis: Clinical efficacy of a new antihistamine Bernard A. Berman, MD Brookline, Mass. Nasal itching, sneezing, and rhinorrhea are troublesome symptoms in patients with perennial allergic rhinitis. Most first-generation H~-receptor agonists achieve a 50% reduction in these symptoms, but their benefits are frequently offset by annoying anticholinergic and sedative side effects. Cetirizine is a major metabolite of hydroxyzine that has little anticholinergic activity and causes significantly less sedation. In addition, it can be given once a day. In placebo-controlled comparisons with terfenadine, both active drugs were comparably effective and significantly better than placebo in relieving sneezing, rhinorrhea, and nasal itching. In a multicenter, double-blind comparison with placebo, both cetirizine, 10 and 20 mg given once daily, were similarly effective and superior to placebo in reducing the overall symptoms of rhinitis. In another multicenter, double-blind study, cetirizine was comparable with diphenhydramine and significantly superior to placebo in reducing total symptom severity, sneezing, rhinorrhea, and ocular itching. The safety of cetirizine was demonstrated in all studies. Cetirizine tended to be less sedating than diphenhydramine. ( J ALLERGY CLIN IMMUNOL 1990;86:1004-8.)

PAR afflicts about 20% of the population. The principal antigens are house-dust mites; saliva, urine, and danders from animals; and mold allergens. Although the signs and symptoms resemble those of seasonal allergic rhinitis, the nasal mucosa in a person with PAR is in a constant state of inflammation. Patients with PAR complain about nasal itching, sneezing, rhinorrhea, and congestion. Most firstgeneration H~-receptor antagonists that are used to treat PAR achieve about a 50% reduction in symptoms, and patients say that they feel fine. However, these medications afford incomplete protection, and many of them have annoying anticholinergic and sedative side effects~ The development of antihistamines that do not cross the blood-brain barrier has been an important advancement in the treatment of allergic rhinitis.~ Cetirizine is a major human metabolite of hydroxyzine but is significantly less sedating than the parent compound and other classic antihistamines in current use. It also has little anticholinergic activity so that patients are not troubled by dry mouth. This article describes several clinical studies of cetirizine in patients with PAR.

From Tufts University and St. Elizabeth's Hospital, Brookline, Mass. Reprint requests: Bernard A. Berman, MD, 1714 Beacon St., Brooktine, MA 02146. 1/0/25849

1004

Abbreviation used

PAR: Perennial allergic rhinitis

CETIRIZINE VERSUS TERFENADINE Schmeisser et al.2 investigated the clinical efficacy of cetirizine, l0 mg given once daily in the evening, compared with terfenadine, 60 mg twice daily, and placebo in 28 patients with moderatey severe to severe PAR. This study, which was conducted outside the pollen season, was a double-blind, crossover design in which patients received each treatment for 2 weeks. The sequence of treatments was determined by randomization. Patients were not permitted to use other antihistamines, corticosteroids, antibiotics, beta-agonists, or anticholinergic drugs for the duration of the study. Although no rescue medications were permitted, patients were allowed to return to the clinic and progress immediately to the next treatment if the current treatment was not effective. Patients were examined before and after each treatment. A 4-point scale was used daily by patients and weekly by clinicians to evaluate the typical symptoms, namely, sneezing, rhinorrhea, nasal congestion, nasal itching, conjunctival itching, and lacrimation.

Results A frank placebo effect was apparent as expected. However, analysis of both investigators' and patients'

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Perennial allergic rhinitis: clinical efficacy of a new antihistamine.

Nasal itching, sneezing, and rhinorrhea are troublesome symptoms in patients with perennial allergic rhinitis. Most first-generation H1-receptor agoni...
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