Elixirium Thymi Compositum in the Treatment of Acute Bronchitis in Pediatric Patients (EXOTIC): Protocol of a Randomized, Double‐Blind Clinical Trial

INTRODUCTION: Acute bronchitis is a common disease caused mainly by viral infections. Although management is primarily symptomatic, antibiotics are frequently prescribed, contributing to antibiotic resistance. Elixirium thymi compositum (Formulae Normale VIII) is a traditional Hungarian herbal medicine that has been used for decades to provide symptomatic relief of acute bronchitis, but lacks robust clinical evidence. This study aims to evaluate the efficacy and safety of Elixirium thymi compositum in the treatment of pediatric acute bronchitis. METHODS AND ANALYSIS: This randomized, controlled, double-blind, superiority trial will enroll 56 patients aged 6-17 years who have been diagnosed with acute bronchitis and have a Bronchitis Severity Score between 5 and 12 points. Participants will be randomly assigned in a 1:1 ratio to receive either Elixirium thymi compositum (18-30 mL daily, depending on age) or a placebo for 5 days. The primary endpoint is symptom improvement, measured by changes in the Bronchitis Severity Score on Day 7. Secondary endpoints include safety and tolerability assessments based on adverse events and the evaluation of concomitant medication use. Data will be collected over a 7-day follow-up period. The Hungarian Medical Research Council Ethics Committee for Clinical Pharmacology and the National Centre for Public Health and Pharmacy Institutional Committee of Science and Research Ethics approved the study protocol (NNGYK/ETGY/03198-4/2025). DISCUSSION: This study will represent the first randomized controlled trial to assess the efficacy of Elixirium thymi compositum for pediatric acute bronchitis. The study results may provide strong evidence to support clinical guidelines and help to ensure that the product continues to be used, based on evidence, to treat pediatric acute bronchitis. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT07030855. Registered 26 June 2025. https://clinicaltrials.gov/study/NCT07030855.