[Show abstract][Hide abstract] ABSTRACT: An acute pharyngitis is characterised by mild to severe sore throat mostly accompanied by inflammation, throat pain, pain on swallowing, and burning. This randomised, double-blind, placebo-controlled phase III study was conducted for comparison of the efficacy and safety of a newly developed lidocaine (2-(diethylamino)-N-(2,6-dimethylphenyl) acetamide, CAS 137-58-6) 8 mg lozenge formulation (Trachisan Halsschmerztabletten) for the treatment of acute sore throat not necessarily to be treated with antibiotics. 240 patients of both genders were enrolled. The study was performed in a single centre setting and consisted of two parts. A 2-h stationary phase (single dose treatment) was directly followed by a 46-h ambulatory phase, where patients were allowed to take up to a maximum of 11 further lozenges (multiple dose treatment). Pain intensity was assessed via Visual Analogue Scale during the course of the study. Moreover, the global efficacy and tolerability of the treatments were assessed. Lidocaine 8 mg sore throat lozenges were found to be superior to placebo for all efficacy parameters investigated. For the primary efficacy parameter, area under the curve of pain intensity from baseline over 2 h (AUC(0-2h)), i.e. after single-dose treatment, a significant treatment difference with a p-value of p < 0.001 in favour of the verum treatment could be demonstrated. Significant superiority could also be demonstrated for the descriptive AUC(0-48h) values, reflecting the treatment effect during the ambulatory multiple dose phase. Pain relief, minimum pain intensity, meaningful pain relief and the time of onset of meaningful pain relief as well as the assessments of global efficacy underlined the superiority of the treatment with lidocaine 8 mg sore throat lozenges. Global tolerability of the verum treatment was rated as "good" or "very good" in the majority of cases, the number of study drug related adverse events was low and evenly distributed to both treatment groups. Therefore, the results of the trial emphasise lidocaine 8 mg sore throat lozenges to be a favourable option in the treatment of pain symptoms of an acute sore throat.