Effects of Oral Procaterol for Postinfectious Cough in Adults: Single-Centre, Randomized Double-Blind, Placebo-Controlled Trial

BACKGROUND: Persistent cough following an upper respiratory tract infection (URTI) is common in clinical practice. We investigated the effects of procaterol on cough-specific quality of life (QoL) and peripheral-airway function among adults suffering from postinfectious cough (PIC). METHODS: This was a prospective, randomized, double-blinded placebo-controlled trial (NCT 02349919) conducted at a university hospital. Seventy-four non-asthmatic adults who had persistent post-URTI cough for ≥3 weeks were assessed by a physical examination, chest/paranasal sinus radiographs, spirometry, and impulse oscillometry (IOS) and were allocated to receive procaterol or placebo for 4 weeks. The Thai version of the Leicester Cough Questionnaire (LCQ-T), spirometry and IOS were assessed at baseline, 2 weeks, and 4 weeks. RESULTS: Mean LCQ-T total scores for the procaterol group (10.8) and placebo group (10.9) at baseline were not significantly different (P=0.821). After adjustment for baseline Borg Cough Scale score and post-nasal drip, the mean between-group difference was not significant for LCQ-T total score (-1.26; 95% confidence interval [CI], -2.69 to 0.17), physical domain score (-0.35; 95% CI, -0.76 to 0.06), psychological domain score (-0.53; 95% CI, -1.06 to 0.01), or social domain score (-0.38; 95% CI, -0.92 to 0.16). Large improvements in LCQ-T total score were reported in both groups after 2 weeks (procaterol, 4.21±2.73; placebo, 5.34±3.2), and 4 weeks (procaterol, 5.94±3.68; placebo, 7.07±3.44). No differences between groups were found in the mean changes of spirometry or IOS parameters after 4 weeks. CONCLUSION: Our study shows that procaterol is not effective in the treatment of PIC, in terms of improvement of cough-specific QoL or peripheral-airway function.