Adult U.S. Poison Center Exposure Case Trends Involving Nonprescription Dextromethorphan Amid the COVID-19 Pandemic:...

Nonprescription dextromethorphan (DXM) is widely available in the United States and was commonly recommended for managing dry cough associated with COVID-19. This retrospective study of Poison Center data evaluated whether the COVID-19 pandemic impacted monthly adult exposure case trends involving nonprescription DXM cold and cough preparations.

We performed interrupted time series analyses using a pre-pandemic baseline period of January 2015-February 2020, and pandemic period of April 2020-April 2023. The pandemic's immediate impact (level change, March 2020) and sustained trend effects were modeled separately by exposure reason categories.

Monthly nonprescription DXM exposure cases declined immediately at the pandemic's onset, and remained low for approximately one year across all age and sex subgroups. Unintentional-therapeutic error exposures subsequently rebounded for some subgroups, particularly females (+ 3 cases/month; 95% CI: 2.7-3.4; p < 0.0001), surpassing pre-pandemic levels by the study's end. Intentional-abuse/misuse exposures had been dramatically declining pre-pandemic; significant trend increase changes were observed among males (+ 0.8 cases/month; 95% CI: 0.5-1.1; p < 0.0001) and adults aged 18-29 years (+ 0.9 cases/month; 95% CI: 0.7-1.1; p < 0.0001) during the pandemic, though the absolute magnitude of these changes was small and warrant cautious interpretation.

Nonprescription DXM exposures declined sharply at the pandemic's onset, with unintentional-therapeutic errors subsequently rebounding - especially among females - surpassing pre-pandemic levels toward the end of the pandemic's public health emergency declaration, while intentional exposures showed modest changes following initial declines. These findings underscore the need for targeted prevention strategies regarding inappropriate nonprescription DXM use and enhanced medication safety messaging during prolonged public health crises.