MODEL FOR OUTCOMES ASSESSMENT OF ANTIHISTAMINE USE FOR SEASONAL ALLERGIC RHINITIS

Background: Drug selection for optimal treatment of common medical con ditions may be difficult and involve may diverse factors. Objective: T he efficacy, safety, quality of life, and cost of treatment of seasona l allergic rhinitis with cetirizine, chlorpheniramine, or terfenadine were compared in a prospective, two-phase, randomized, single-blind cl inical trial conducted in a managed care setting. Methods: In phase I, which lasted 2 weeks, patients were randomized to receive one of the study drugs. In phase II, which lasted 4 weeks, the initial treatment was continued unless patients were dissatisfied, in which case they co uld be randomly assigned to receive another study drug. In both phases pseudoephedrine could be taken as needed. Patients kept daily diaries of symptoms and costs, and study drugs were evaluated at the end of e ach phase for efficacy, safety, and effect on quality of life by means of validated questionnaire. A multiattribute outcomes assessment mode l for formulary decision making was used to rank the antihistamines. R esults: Physicians' and patients' assessments in phase I and II indica ted that cetirizine and chlorpheniramine were significantly more effec tive than terfenadine (p < 0.05). Incidence of sedation in phase I and phase II was 40.5% and 16.7% for chlorpheniramine, 11.6% and 9.8% for cetirizine, and 6.7% and 5.1% for terfenadine, respectively. At the e nd of phase I, 28.9% of the patients treated with chlorpheniramine, 50 % of the patients treated with terfenadine, and 69.4% of the patients treated with cetirizine were satisfied with their therapy and chose no t to switch their medication. Quality of life scores improved most aft er treatment with cetirizine and least after treatment with terfenadin e. Conclusion: The results of this trial indicate that antihistamine s election is best made with the use of a multiattribute evaluation that includes quality of life. In this study cetirizine was favored by pat ients and physicians most often, followed by chlorpheniramine and then terfenadine.