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 </= 0.05) relief of rhinorrhea and nasal stuffiness as compared with placebo. Insomnia was reported significantly more often (P < 0.01) in Claritin-D 12 Hour (15%) patients compared with Claritin-D 24 Hour (4%) and placebo (2%) patients. Dry mouth was reported significantly more often (P < 0.05) in Claritin-D 24 Hour (13%) and Claritin-D 12 Hour (13%) groups compared with placebo (4%). Claritin-D 24 Hour has efficacy comparable to Claritin-D 12 Hour in relieving allergic rhinitis symptoms while producing significantly less insomnia.