Effectiveness of desloratadine 5 mg once daily in patients with symptoms of seasonal allergic rhinitis: results of a Canadian multicenter, open-label trial.

BACKGROUND

Seasonal allergic rhinitis (SAR) is an inflammatory response to seasonal allergens. Desloratadine, a once-daily selective histamine H(1)-receptor antagonist, has been reported to be efficacious in relieving symptoms of SAR in controlled clinical trials. However, to assess the actual effectiveness of a drug, it is important to examine information about its use in routine clinical practice.

OBJECTIVE

The Partners in Allergy Control and Therapy (PACT) study examined the effectiveness of desloratadine in patients with SAR symptoms receiving treatment in a community setting of primary care physicians in Canada.

METHODS

Patients with symptoms of SAR received desloratadine 5 mg once daily for 7 days during the spring-summer allergy season (April-July 2002). Patients rated their SAR symptoms along with their physicians by completing a questionnaire at baseline and day 7. Nasal, ocular, respiratory, and overall symptoms were rated on a scale of 0 (no symptoms evident) to 3 (severe/interfere with activities of daily living and/or sleeping). Physicians were asked to keep a record of adverse events reported by patients. The Wilcoxon signed-rank test was used to evaluate symptom severity scores. A 2-way (time x treatment), repeated measures, mixed analysis of variance (ANOVA) model was constructed to assess differences in variables over time.

RESULTS

A total of 6829 patients participated in the study. Patients reported nasal stuffiness/congestion as their most severe symptom. Just over half (50.1%) of patients were receiving another medication for SAR at study entry; 29.7% were receiving an intranasal corticosteroid. After 7 days of treatment with desloratadine, individual symptom scores and overall symptom scores were significantly reduced compared with baseline (all scores, P<0.001). An improvement in nasal/stuffiness/ congestion was reported by 88.0% of patients. The ANOVA detected a statistically significant incremental benefit with desloratadine and an intranasal corticosteroid compared with desloratadine monotherapy (P<0.001). No severe adverse events were reported.

CONCLUSION

Desloratadine 5 mg once daily was associated with significant improvement in symptoms of SAR, and appeared to provide additional benefit in relieving moderate to severe nasal stuffiness/congestion in 6786 patients receiving 7-day treatment in an actual practice setting of primary care physicians in Canada.