In a randomized pilot clinical study, Dextromethorphan hydrobromide demonstrated antitussive effectiveness in children, employing validated assessment tools for both objective and subjective evaluations commonly used in pediatric populations. The primary objective of the study was to identify the most appropriate measures for assessing the antitussive effectiveness of Dextromethorphan in pediatric patients.

This multiple-dose, double-blind, placebo-controlled study enrolled children between the ages of 6 and 11 who had cough caused by the common cold. To qualify for the study, participants had to meet specific criteria and undergo a run-in period where their coughs were monitored using a cough monitor after taking a sweet syrup. After the run-in period, the children were randomly assigned to get either Dextromethorphan or a placebo for a duration of 4 days.

Recording of coughs was done within the first 24 hours, and the children self-reported their subjective assessments of cough frequency and severity on a daily basis throughout the treatment period. The analysis included data from 128 eligible participants, with 67 receiving Dextromethorphan and 61 receiving the placebo. The major outcome, which measured total coughs over a 24-hour period, showed a significant reduction of 21.0% with Dextromethorphan compared to the placebo.

Additionally, Dextromethorphan demonstrated a 25.5% decline in cough frequency during the daytime. The participants also reported a higher decline in both cough frequency and severity when taking Dextromethorphan. These findings were both medically relevant and statistically significant. However, no significant differences were observed between the treatments regarding nighttime cough rates or the impact of cough on sleep. Overall, multiple doses of both Dextromethorphan and the placebo were well-tolerated by the volunteers.

The effectiveness of Dextromethorphan as a cough suppressant in children was supported by evidence obtained through the use of validated objective and subjective assessment tools commonly used in pediatric populations. It was observed that the sensitivity of the assay to detect treatment differences at nighttime was reduced due to the diurnal variation of cough frequency over a 24-hour period. This reduction in coughs per hour during sleep was observed in both the Dextromethorphan and control groups.