Comparative Study of Apo-Cetirizine Single Therapy and Intermittent Sequential Therapy with Cetirizine, Loratadine and Chlorpheniramine in Allergic Rhinitis.

There are limited numbers of articles, studying combined use of antihistamines. In this study, we compare single therapy of Apo-Cetirizine with a new regimen of intermittent sequential therapy with cetirizine, loratadine and chlorpheniramine in treatment of seasonal allergic rhinitis. This randomized clinical trial was performed between April and September at the peak prevalence of seasonal allergic rhinitis. Fifty-four eligible patients diagnosed clinically to have seasonal allergic rhinitis were randomized in two groups: 24 cases in single therapy arm, received Apo-Cetirizine 10 mg tablet daily and in other arm, 30 patients received sequential regimen of cetirizine 10 mg tablet, loratadine 10 mg tablet and chlorpheniramine 4 mg tablet, one tablet each day. Major Symptom Complex Score (MSCS) and Total Symptom Complex Score (TSCS) of patients were recorded before treatment and after 30 days of treatment in two groups. The average post-treatment MSCS and TSCS in combination therapy group showed better improvement than single therapy group but difference was not statistically significant (p value = 0.053 and p value = 0.104 respectively). Combination therapy regimen was better in improvement of nasal congestion (p value = 0.006). There were no significant difference between two groups in efficacy, side effects and patient's satisfaction. Combination therapy would be effective on a wide spectrum of symptoms with lower price and theoretically offers lower chance of tolerance and re-appearance of complaints.