Background: Nonsedating antihistamines are well-established treatment for seasonal allergic rhinitis (SAR), but patients do not always respond to the first antihistamine prescribed.
Objective: This double-blind, double-dummy, randomized, 2-phase, multicenter study was designed primarily to compare the therapeutic responses to loratadine and fexofenadine in patients who failed initial therapy with the other drug.
Methods: Male and female patients aged 12 to 60 years received loratadine 10 mg once daily (n = 331) or fexofenadine 60 mg twice daily (n = 328) for 14 days (phase 1); nonresponders (ie, those who had <25% reduction in the sum of 5 SAR symptoms rated by the investigator on a 4-point scale) subsequently received the alternate medication for 14 days (phase 2). The investigator's rating of relief (complete, marked, moderate, or slight relief of symptoms or treatment failure) at the end of phase 2 was the primary efficacy measure; changes in total symptom severity (TSS) assessed by the investigator (4-point scale) and the patient (11-point visual analog scale) were secondary measures.
Results: Mean decreases in TSS were significantly greater with loratadine than with fexofenadine for the 659 patients who completed phase 1 (-12.7 vs -10.2, respectively; P = 0.019; patient assessment) and for the 389 patients who responded to initial therapy (-6.6 vs -6.1, respectively; P = 0.037; investigator assessment). Of the 389 patients who responded to initial therapy, 61.0% had received loratadine and 57.0% had received fexofenadine. More nonresponders to initial therapy had moderate, marked, or complete relief of symptoms after switching to loratadine than after switching to fexofenadine (62.4% vs 51.2%, respectively; P = 0.005) and treatment failure in 10.6% vs 21.7%, respectively (P = 0.011).
Conclusion: Overall, ioratadine provided significantly better therapeutic response than fexofenadine in patients who failed to respond to initial therapy with the other drug.