Association between marijuana use and nonmedical prescription opioid use in the United States: are we shifting from one epidemic to another?

The United States (US) is grappling with a severe opioid epidemic. Marijuana is emerging as a therapy for pain management and an alternative to opioids, but little evidence supports its long-term benefits. This study aims to examine the association of marijuana use among patients on prescription pain relievers in a retrospective cross-sectional study using zero-inflated negative binomial regression. The recipients of prescription pain medicines were identified using National Survey on Drug Use and Health (2015–2017). Irrespective of the state marijuana laws, marijuana use days were 34% higher and odds of having zero days of marijuana use were 73% lower in those using nonmedical prescription opioids vs. not (IRR = 1.34, p