Age-Related and Temporal Patterns of Dextromethorphan Abuse Reporting in VigiBase: A Disproportionality Analysis

Objective: Dextromethorphan (DXM) is an over-the-counter antitussive with abuse potential.This study evaluated DXM abuse-related reporting disproportionality and age-specific temporal patterns using World Health Organization (WHO) VigiBase.Methods: We conducted a retrospective disproportionality analysis of individual case safety reports from the Region of the Americas reported between October 1, 2019 and September 30, 2024.Drug-adverse event pairs were the unit of analysis.Abuse-related events were defined using the Standardised Medical Dictionary for Regulatory Activities Query (SMQ) "Drug abuse and dependence."Reporting odds ratio (ROR), proportional reporting ratio (PRR), information component (IC), and chi-square statistics were calculated.Age-and year-stratified, comparator, and sensitivity analyses were performed.Results: Among 7,897,723 reports and 27,544,108 drug-adverse event pairs, 3,714 pairs involved DXM.DXM showed an overall abuse-related reporting signal (ROR 6.16, 95% confidence interval [CI] 5.65-6.70;PRR 5.27; lower bound of the 95% credibility interval for the information component (IC025) 2.31; chi-square 2274.52).Stratified analyses showed a common ROR peak in 2022 among the 12-17, 18-44, and 45-64-year age groups.The most interpretable pattern was observed in individuals aged 18-44 years, where the 2022 ROR increase coincided with the largest abuse-related case count among age groups showing a 2022 peak.Comparator and sensitivity analyses supported this finding.Conclusion: DXM was associated with disproportionate reporting of abuse-related adverse events in VigiBase.The 2022 peak, particularly among individuals aged 18-44 years, should be interpreted as a pharmacovigilance signal rather than evidence of increased incidence or causality.These findings support continued monitoring and age-informed risk communication for over-thecounter medications with abuse potential.(PeRM 2026;18:199-210)