Lidocaine throat spray effective in patients with refractory chronic cough, Study says

The study is published in the Journal of Allergy and Clinical Immunology.

Refractory chronic cough (RCC) is a debilitating condition for which there are no licensed treatments. Lidocaine is a nonselective inhibitor of voltage-gated sodium channels with potential antitussive effects, but randomized placebo-controlled studies evaluating its efficacy in RCC are lacking.

Hence, Rayid Abdulqawi and colleagues from the University of Manchester, Division of Infection, Immunity and Respiratory Medicine, and Manchester Academic Health Science Centre, Manchester, United Kingdom conducted the present study with the objective to investigate the efficacy of nebulized lidocaine and lidocaine throat spray versus matched placebos in RCC.

The authors carried out a randomized, double-blind, double-dummy, placebo-controlled, 3-way crossover study, comparing the effect of single doses of nebulized lidocaine with lidocaine delivered by a throat spray and matched placebo.

The primary end point was cough frequency over the 10 hours following treatment. Secondary end points were visual analog scale scores for urge-to-cough and cough severity; an exploratory analysis evaluated hourly cough rates up to 5 hours after treatment.

The results revealed that-

3. Twenty-six subjects with RCC were recruited (22 females; mean age, 53.5 ± 12.1 years; FEV1 %predicted, 105.2 ± 16.8 L; forced vital capacity %predicted, 112.4 ± 18 L).
4. Lidocaine throat spray, but not nebulized lidocaine, significantly reduced 10-hour cough frequency as compared with placebo (throat spray, 22.6 coughs/h; nebulization, 26.9 coughs/h; and placebos, 27.6 coughs/h; P = .04,).
5. Lidocaine throat spray showed the greatest effect on cough compared with placebo in the first hour after administration (31.7 coughs/h vs 74.2 coughs/h; P = .004).
6. Both nebulizer and spray treatments significantly alleviated urge-to-cough and cough severity visual analog scale scores compared with placebo (P < .05).
7. There were no serious adverse events associated with lidocaine therapy.

Therefore, the authors concluded that "Lidocaine throat spray was effective in reducing cough frequency in patients with RCC. Voltage-gated sodium channel inhibitors applied to pharynx have potential as therapies for RCC."