Efficacy and safety of modified sequential three-step empirical therapy for chronic cough.

Sequential three-step empirical therapy is useful for the management of chronic cough. The purpose of this study was to evaluate the efficacy and safety of modified sequential three-step empirical therapy. Consecutive patients (n = 240) with chronic cough were recruited and randomly assigned to receive modified (modified group) or primary (primary group) sequential three-step empirical therapy. The primary end-point was the overall rate of control of chronic cough. Secondary end-points were the rate of control of chronic cough at each step of therapy, the duration of treatment required, changes in cough symptom score, health-related quality of life and possible adverse effects. The study was completed by 106 patients in the modified group and 108 patients in the primary group. The overall rate of control of chronic cough was 88.7% in the modified group and 91.7% in the primary group (chi(2) = 0.54, P > 0.05). There were no obvious differences in the rate of control of cough at each step of therapy, the duration of treatment required, patterns of cough symptom scores or improvements in the health-related quality of life between the modified and primary groups. However, the incidence of drowsiness was significantly lower in the modified group than in the primary group (11.7% vs 21.7%, chi(2) = 4.32, P = 0.04). Modified three-step empirical therapy was as efficacious as primary three-step therapy for chronic cough, but was preferable because it had fewer side-effects.