Efficacy of diphenhydramine vs desloratadine and placebo in patients with moderate-to-severe seasonal allergic rhinitis.

BACKGROUND

Previous studies have shown that diphenhydramine and desloratadine effectively relieve symptoms of seasonal allergic rhinitis (SAR).

OBJECTIVE

To compare the relative efficacy of 50 mg of diphenhydramine hydrochloride, 5 mg of desloratadine, and placebo in relieving symptoms in patients with moderate-to-severe SAR.

METHODS

In this 1-week, multicenter, parallel-group, randomized, double-blind, double-dummy, placebo-controlled study, 610 patients with moderate-to-severe SAR received 50 mg of diphenhydramine hydrochloride 3 times daily, 5 mg of desloratadine once daily, or placebo. Daily 24-hour reflective total nasal symptom scores (TNSSs) (primary end point), total symptom scores, and individual symptom scores were evaluated. A global evaluation of response to treatment was conducted at 2 posttreatment visits.

RESULTS

The mean reduction from baseline in 24-hour reflective TNSSs relative to the placebo response was 77.6% for the diphenhydramine group (P < .001) and 21.0% for the desloratadine group (P = .12). A TNSS between-treatment difference of -1.81 (46.7%; P < .001) was observed when comparing diphenhydramine with desloratadine. A similar between-treatment difference was observed for the 24-hour reflective total symptom score comparing diphenhydramine to desloratadine (-3.35; 45.5%; P < .001). Diphenhydramine provided clinically and statistically significant reductions vs placebo and desloratadine in all individual symptoms, including nasal congestion. Desloratadine had a tendency toward improvement compared with placebo for most individual symptom scores. However, a statistically significant result was reached only for sneezing (-0.27; 33.9%; P = .04).

CONCLUSIONS

Diphenhydramine, 50 mg, given for 1 week provided statistically significant and clinically superior improvements in symptoms compared with 5 mg of desloratadine in patients with moderate-to-severe SAR. Somnolence occurred more frequently with diphenhydramine (22.1%) compared with desloratadine (4.5%) and placebo (3.4%).