LACK OF EFFECT OF LORATADINE ON MODERATE TO SEVERE ASTHMA

Background: Antihistamines have been shown to be effective in patients with allergic asthma, but their role in chronic and more severe asthm a is uncertain. Objectives: To evaluate whether loratadine, a selectiv e H-1 receptor antagonist, given as sn adjunct to standard asthma medi cation would have any effect in patients with moderate-to-severe asthm a. Methods: Thirty-five patients with moderate-to-severe asthma, most receiving inhaled steroids, were enrolled in this double-blind crossov er study. In addition to their maintenance therapy patients received e ither loratadine, 20 mg once daily, or placebo for 4 weeks before cros sing over to the other preparation for a further 4 weeks. Variables of efficacy were daily and nocturnal respiratory symptoms, lung function (PEF, FEV(1), FVC), and bronchodilator use. Results: Three subjects w ere withdrawn from the study because of deteriorating asthma. There wa s a trend in favor of loratadine treatment with regard to global asses sment of drug efficacy but the difference was not statistically signif icant. There was no objective improvement in asthma control comparing loratadine with placebo but if each treatment week were compared with the run-in period, PEF was significantly (P<.01) improved during the i nitial phase of loratadine treatment. This effect gradually decreased with time, suggesting tolerance to any bronchodilatory effect of the a ntihistamine. Conclusion: Loratadine, given as an adjunct to standard asthma therapy, has little if any role to play in the treatment of mod erate-to-severe asthma.