Comparative efficacy and safety of once-daily versus twice-daily loratadine-pseudoephedrine combinations versus placebo in seasonal allergic rhinitis.

The objective of this study was to compare the efficacy and safety of Claritin-D 24 Hour (once daily) with that of Claritin-D 12 Hour (twice daily) and placebo in the treatment of patients with seasonal allergic rhinitis (SAR). In this double-blind, placebo-controlled, multicenter study, 469 patients with moderate-to-severe SAR symptoms were treated for 2 weeks with one of the following: Claritin-D 24 Hour (a combination tablet formulation of loratadine 10 mg in the coating and pseudoephedrine sulfate 240 mg in an extended-release core), Claritin-D 12 Hour (a combination tablet formulation of loratadine 5 mg in the tablet coating and 120 mg pseudoephedrine sulfate, 60 mg in the coating and 60 mg in the core), or placebo. Claritin-D 24 Hour and Claritin-D 12 Hour were consistently superior to placebo (P < 0.01) in reducing total, nasal, and nonnasal symptom scores. Patients in the Claritin-D 24 Hour and Claritin-D 12 Hour groups also had significantly greater (P