A member of a new P2X3 antagonist class of antitussives for refractory or unexplained chronic cough, gefapixant 45 mg orally twice daily modestly improved cough frequency, cough severity, and cough-specific quality of life but increased taste-related adverse events in patients with refractory or unexplained chronic cough in randomized controlled trials included a systematic review and meta-analysis.
“Nine RCTs including 2,980 patients were included in the primary analysis,” the authors write. “Compared with placebo, gefapixant (45 mg twice daily) had small effects on awake cough frequency (17.6% reduction [95% CI, 10.6%-24.0%], moderate certainty), cough severity on the 100-mm [visual analog scale] (mean difference, −6.2 mm [95% CI, −4.1 to −8.4]; high certainty), and cough-specific quality of life on the [Leicester Cough Questionnaire] (mean difference, 1.0 points [95% CI, 0.7-1.4]; moderate certainty). Compared with placebo, gefapixant (45 mg twice daily) probably caused an important increase in treatment-related adverse events (32 more per 100 patients [95% CI, 13-64 more], moderate certainty) and taste-related adverse events (32 more per 100 patients [95% CI, 22-46 more], high certainty). High-certainty evidence suggests that gefapixant (15 mg twice daily) had small effects on taste-related adverse events (6 more per 100 patients [95% CI, 5-8 more]).”