Patterns and correlates of medical cannabis use for pain among patients prescribed long-term opioid therapy.

OBJECTIVE: Little is known about co-occurring long-term opioid therapy (LTOT) and medical cannabis use. We compared characteristics of patients prescribed LTOT who endorsed using medical cannabis for pain to patients who did not report cannabis use.

METHOD: Participants (n=371) prescribed LTOT completed self-report measures about pain, substance use, and mental health.

RESULTS: Eighteen percent of participants endorsed using medical cannabis for pain. No significant differences were detected on pain-related variables, depression, or anxiety between those who endorsed medical cannabis use and those who did not. Medical cannabis users had higher scores of risk for prescription opioid misuse (median=17.0 vs. 11.5, p<0.001), rates of hazardous alcohol use (25% vs. 16%, p<0.05), and rates of nicotine use (42% vs. 26%, p=0.01). Multivariable analyses indicated that medical cannabis use was significantly associated with risk of prescription opioid misuse (β=0.17, p=0.001), but not hazardous alcohol use (aOR=1.96, 95% CI=0.96-4.00, p=0.06) or nicotine use (aOR=1.61, 95% CI=0.90-2.88, p=0.11).

CONCLUSION: There are potential risks associated with co-occurring LTOT and medical cannabis for pain. Study findings highlight the need for further clinical evaluation in this population. Future research is needed to examine the longitudinal impact of medical cannabis use on pain-related and substance use outcomes.