Efficacy and Safety of an Oral Ambroxol Spray in the Treatment of Acute Uncomplicated Sore Throat

Objective: Compare the efficacy and tolerability of oral spray formulations delivering 2.5, 5, and 10 mg ambroxol (AXS) per application (4 actuations/application) in relieving acute sore throat vs. spraying a matched placebo solution. Design: Multi-centre, placebo-controlled, randomised, double-blind trial with up to 6 daily applications of the assigned medication for up to 3 days. Patients: 511 outpatients with acute sore throat were enrolled, 494 were treated. Treatments: Up to 6 spray applications per day as needed for up to 3 days. Results: All treatments led to a reduction in pain intensity (PI); the mean cumulative PI-reductions over the first 2 h after the 1st dose (SPIDnorm(0-2)) were 24.7, 26.6, 26.0, and 32.2% (SEM: 0.023) of the predose PI for treatment with placebo, and the 2.5, 5, and 10 mg AXS, respectively. These mean reductions were 2 (CI: -3.6; 7.5), 1.3 (CI: -4.3; 6.8), and 7.5 (CI: 2.0;13.1) percent points larger than for placebo. The 2.5 and 5 mg AXS were not distinguishable from placebo, but the 10 mg AXS was evidently superior. The numbers needed to treat (NNT) when comparing 10 mg AXS with placebo, were 9.5 and 8.8 for an average pain relief of 33 and 50% of the maximum achievable effect over the first 2 h. Conclusions: 10 mg AXS showed a statistically significantly superior pain reduction relative to the placebo spray. Treatment with 10 mg AXS reaches an extent of pain relief that can be accepted to be clinically meaningful and was well tolerated.