Desloratadine for Allergic Rhinitis

SHARON SEE, PHARM.D., St. John's University College of Pharmacy and Allied Health Professions
Jamaica, New York, and Beth Israel Residency in Urban Family Practice, New York, New York

Synopsis: Desloratadine (Clarinex) is the orally active metabolite of the nonsedating histamine-1 (H₁) receptor antagonist loratadine (Claritin). It is indicated for seasonal and perennial allergic rhinitis and chronic idiopathic urticaria in patients 12 years of age and older.

Name Starting dosage Dose forms Monthly cost* Desloratadine (Clarinex) Adults and children >=12 years of age: 5 mg orally daily 5-mg tablets $67   Renal/hepatic impairment: 5 mg orally every other day     *--Average wholesale costs are based on Red Book. Montvale, N.J.: Medical Economics Data, 2003.

Safety: There are no major safety issues associated with desloratadine. It does not have any adverse cardiovascular effects or cause the heart conduction changes that have occurred with other second-generation antihistamines. Desloratadine is category C in pregnancy, and passes through the milk during breastfeeding. Loratadine is minimally excreted in the breast milk (<0.1 percent) after oral doses.¹ While this may indicate safety with desloratadine, confirmatory studies are needed. The manufacturer recommends that women discontinue breastfeeding if they choose to take desloratadine.

STEPS drug updates cover Safety, Tolerability, E ffectiveness, Price, and S implicity.

Tolerability: Desloratadine is well tolerated. The type and number of side effects associated with desloratadine are similar to those associated with placebo. The most common adverse events are headache, fatigue, and dry mouth, which occur in 2 to 3 percent of people.

Effectiveness: Desloratadine decreases both nasal symptoms (rhinorrhea, congestion, nasal itching, and sneezing) and nonnasal symptoms (itchy, watery, red eyes, and itchy ears) in patients with seasonal allergic rhinitis. The benefit is statistically significant but not very impressive clinically: approximately 0.25 points on a 3-point scale compared with placebo in both categories.^2,3 Desloratadine also is effective for chronic idiopathic urticaria.⁴ Over six weeks, desloratadine reduced pruritus symptom scores by 74 percent compared with 48.7 percent for placebo (P<.001). A well-designed randomized crossover trial found that desloratadine is no more effective than fexofenadine (Allegra) at usual therapeutic dosages in relieving symptoms of seasonal allergic rhinitis.⁵

Price: A one-month supply of desloratadine costs between $60 and $70, similar to the cost of other prescription antihistamines such as fexofenadine and cetirizine (Zyrtec). This is about twice the cost of nonprescription loratadine and is much more expensive than other nonprescription antihistamines.

Simplicity: Desloratadine is available in 5-mg tablets. The daily dose in patients older than 12 years is 5 mg once a day. Patients with renal or hepatic impairment should take 5 mg every other day.

Bottom line: Desloratadine is somewhat effective for the treatment of seasonal allergic rhinitis and may decrease nasal congestion. It also is effective for chronic urticaria. Desloratadine is similar in effectiveness to fexofenadine and would be expected to produce results similar to loratadine and other nonsedating antihistamines. There is no clinical advantage to switching a patient from loratadine to desloratadine. However, it may be an option for patients whose medical insurance no longer covers loratadine if the co-pay is less than the cost of the over-the-counter product.

REFERENCES

1. Hilbert J, Radwanski E, Affrime MB, Perentesis G, Symchowicz S, Zampaglione N. Excretion of loratadine in human breast milk. J Clin Pharmacol 1988; 28:234-9.
2. Berger WE, Schenkel EJ, Mansfield LE. Desloratadine Study Group. Safety and efficacy of desloratadine 5 mg in asthma patients with seasonal allergic rhinitis and nasal congestion. Ann Allergy Asthma Immunol 2002;89:485-91.
3. Meltzer EO, Prenner BM, Nayak A. Efficacy and tolerability of once-daily 5mg desloratadine, an HSUB1-receptor antagonist, in patients with seasonal allergic rhinitis: assessment during the spring and fall allergy seasons. Clin Drug Invest 2001;21:25-32.
4. Ring J, Hein R, Gauger A, Bronsky E, Miller B. Once-daily desloratadine improves the signs and symptoms of chronic idiopathic urticaria: a randomized, double-blind, placebo-controlled study. Int J Dermatol 2001;40:72-6.
5. Wilson AM, Haggart K, Sims EJ, Lipworth BJ. Effects of fexofenadine and desloratadine on subjective and objective measures of nasal congestion in seasonal allergic rhinitis. Clin Exp Allergy 2002; 32:1504-9.

The series coordinator of STEPS is Allen F. Shaughnessy, Pharm.D., director of medical education at Pinnacle Health System, Harrisburg, Pa.

Sharon See, Pharm.D., is assistant clinical professor in the Clinical Pharmacy Practice Department of St. John's University College of Pharmacy and Allied Health Professions, Jamaica, N.Y. She also is clinical coordinator of the Beth Israel Residency in Urban Family Practice, New York, N.Y.

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