Abstract
CONTEXT: Cocaine and metamfetamine use and overdose deaths among United States adults have been increasing in recent years. We examined associations of medical outcomes with co-used opioids and other substances among cocaine, and metamfetamine exposures in people age ≥50 years (N = 9300) reported to the National Poison Data System, 2015-2021. METHODS: We first described increases in these exposures over time. We fitted generalized linear models for a Poisson distribution with a log link, one for cocaine exposures and the other for metamfetamine exposures, to examine associations of medical outcomes (major effects/death versus all others) with co-used other substances, controlling for exposure year and demographics. RESULTS: The number of exposures increased steadily during the seven years, but metamfetamine exposures increased more rapidly starting in 2018. One-fifth of cocaine and one-sixth of metamfetamine exposures suffered major effects/death. Co-use of prescription opioids (incident risk ratio = 2.00, 95% CI = 1.76-2.28 for cocaine; incident risk ratio = 1.62, 95% CI = 1.27-2.07 for metamfetamine), illicit fentanyl (incident risk ratio =1.88, 95% CI = 1.08-3.27 for cocaine; incident risk ratio = 2.05, 95% CI = 1.04-4.06 for metamfetamine), heroin (incident risk ratio =1.62, 95% CI = 1.37-1.90 for cocaine), or amfetamine (incident risk ratio =1.73, 95% CI = 1.28-2.33 for cocaine) was associated with a higher likelihood of major effects/death. DISCUSSION: Increases in the number of cocaine and metamfetamine exposures among older adults reported to poison centers are of concern, and so is the increased risk of major effects/death from polysubstance use, especially prescription and illicit opioids, among these illicit psychostimulant users. CONCLUSIONS: Healthcare provider screening of individuals at risk of cocaine and/or metamfetamine use and psychoeducation about the dangers of these substance use are needed.