Randomised, Double-Blind, Placebo-Controlled Study of a Single Dose of an Amylmetacresol/2,4-dichlorobenzyl Alcohol Plus Lidocaine Lozenge or a Hexylresorcinol Lozenge for the Treatment of Acute Sore Throat Due to Upper Respiratory Tract Infection

Purpose: Sore throat is a frequent reason for seeking medical care but few prescription options are available. Lozenges are effective in delivering active ingredients to the throat. This study was conducted to determine the analgesic efficacy of two lozenges - one containing amylmetacresol (AMC)/2,4-dichlorobenzyl alcohol (DCBA) and lidocaine and one containing hexylresorcinol. versus placebo in patients with acute sore throat due to upper respiratory tract infection (URTI). Methods: This was a multicentre, randomised, double-blind, parallel group, placebo-controlled study. In total, 190 patients were randomised 1: 1: 1 to a single dose of AMC/DCBA + lidocaine, hexylresorcinol or placebo lozenge. Subjective ratings of throat soreness, difficulty swallowing, swollen throat, numbing, and sore throat relief were obtained up to 2 hours post dose. Patient and investigator global ratings and a consumer questionnaire were also collected. The primary endpoint was the change from baseline in severity of throat soreness for both lozenges versus placebo at 2 hours post dose. Results: The hexylresorcinol lozenge demonstrated superiority over placebo for primary and secondary efficacy variables including those related to throat soreness, sore throat relief and difficulty swallowing; the AMC/DCBA + lidocaine lozenge was also superior to placebo for secondary endpoints at various time points but did not reach significance for the primary efficacy variable. Both lozenges had a rapid onset of action from 1-10 minutes post dose for the AMC/DCBA + lidocaine lozenge and 1-5 minutes post dose for the hexylresorcinol lozenge. Numbness was reported from 1 minute post dose with the AMC/DCBA + lidocaine lozenge and was greatest at 15 minutes. Numbness was reported from 5 minutes post dose with the hexylresorcinol lozenge and was greatest at 10 minutes. Both lozenges were well tolerated. Conclusions: Both AMC/DCBA + lidocaine and hexylresorcinol lozenges provided rapid and effective sore throat relief in patients with URTI.