AMBER trial (amla-based extract for endobronchial ultrasound cough reduction): A randomized controlled study

Cough during endobronchial ultrasound (EBUS) is common and can reduce patient comfort, prolong procedures, and compromise diagnostic yield. While dextromethorphan has demonstrated antitussive efficacy, concerns remain regarding side effects and availability. Emblica officinalis (Amla) is a traditional herbal medicine with reported antitussive properties, but human evidence is lacking.

This study evaluated the efficacy of E. officinalis compared with dextromethorphan and their combination as premedication for cough suppression in patients undergoing advanced EBUS.

In this randomized, double-blind, placebo-controlled trial, 118 patients undergoing EBUS were allocated to placebo, dextromethorphan 60 mg, E. officinalis extract 600 mg, or their combination. Cough events were recorded throughout the procedure. The primary outcome was total cough count. Secondary outcomes included oxygen desaturation, sedative/analgesic requirements, procedure difficulty, and patient-reported discomfort.

Median cough counts were 61.0 (IQR 26.3-90.8) in placebo, 20.0 (5.0-27.0) with dextromethorphan, 27.0 (14.0-40.0) with E. officinalis, and 25.5 (15.3-29.0) with the combination. Kruskal-Wallis testing showed significant group differences (p = 0.019, rank η²=0.061). All active treatments reduced cough versus placebo (p < 0.05), with no differences among active arms. E. officinalis reduced oxygen desaturation, while dextromethorphan lowered sedative requirements. No adverse events occurred.

E. officinalis significantly reduced cough during EBUS, with efficacy comparable to dextromethorphan and an excellent safety profile. These findings suggest E. officinalis may serve as a safe, cost-effective alternative premedication for cough suppression in advanced bronchoscopy.