Lidocaine throat spray reduces cough frequency in patients with refractory chronic cough

Lidocaine, delivered as a throat spray to the pharynx, reduced cough frequency in adults with refractory chronic cough, according to data published in the Journal of Allergy and Clinical Immunology: In Practice.

“This is the first placebo-controlled study to evaluate the effects of inhaled and topical lidocaine in patients with chronic cough. Contrary to our expectations, we demonstrated that a single dose of lidocaine throat spray resulted in a significant reduction in objective cough frequency in patients with refractory chronic cough, compared with both nebulized lidocaine and placebo,” Rayid Abdulqawi, MBBS, MRCP, PhD, honorary senior lecturer in the division of infection, immunity and respiratory medicine at the University of Manchester and Manchester Academic Health Science Centre, U.K., and adjunct assistant professor in the department of medicine at Alfaisal University and consultant in internal and pulmonary medicine at Dr. Sulaiman Al Habib Medical Group in Riyadh, Saudi Arabia, and colleagues wrote.

The randomized, double-blind, double-dummy, placebo-controlled, crossover study included 26 participants (mean age, 53.5 years; 84.6% women) with refractory chronic cough. Participants were randomly assigned to nebulized lidocaine 600 mg followed by placebo throat spray, nebulized placebo followed by placebo throat spray or nebulized placebo followed by lidocaine 100 mg delivered by throat spray.

The primary outcome measure was cough frequency within 10 hours after treatment. Secondary outcomes included visual analog scale scores for urge-to-cough and cough severity.

The group that received lidocaine throat spray but not nebulized lidocaine had reduced cough frequency 10 hours after treatment compared with placebo (22.6 coughs per hour vs. 27.6 coughs per hour with placebo spray and 26.9 coughs per hour with nebulized lidocaine; P = .04).

The greatest effect on cough reduction occurred in the first hour after administration with lidocaine throat spray compared with placebo (31.7 coughs per hour vs. 74.2 coughs per hour; P = .004).

For secondary outcomes, nebulizer and lidocaine throat spray cough treatments reduced the urge-to-cough and cough severity visual analog scale scores compared with placebo (P < .05).

The researchers reported no serious adverse events associated with lidocaine throat spray.

“This study provides proof-of-concept evidence that blocking [voltage-gated sodium channels] has antitussive effects in patients with refractory chronic cough,” the researchers wrote.