BACKGROUND:

Co-prescribing of scheduled drugs is endemic in the United Sates, increasing health risks to patients and the burden on healthcare systems.

PURPOSE:

We conducted a pragmatic historical cohort study to measure the effect of enrollment in a state-authorized United States’ Medical Cannabis Program (MCP) on scheduled II-V drug prescription patterns.

PROCEDURES:

Eighty-three chronic pain patients, who enrolled in the New Mexico MCP between April 1, 2010 and October 3, 2015, were compared with 42 nonenrolled patients over a 24-month period (starting 6 months before enrollment for the MCP patients) using the Prescription Monitoring Program. The outcome variables include baseline levels and pre- and postenrollment monthly trends in the number of drug prescriptions, distinct drug classes, dates prescription drugs were filled, and prescribing providers.

FINDINGS:

Twenty-eight MCP patients (34%) and 1 comparison group patient (2%) ceased the use of all scheduled prescription medications by the last 6 months of the observation period. Age- and sex-adjusted regressions show that, although no statistically significant differences existed in pre-enrollment levels and trends, the postenrollment trend among MCP patients is statistically significantly negative for all 4 measures (decreases in counts of -0.02 to -0.04, P values between <.001 and .017), whereas the postenrollment trend is 0 among the comparison group. Controlling for time-invariant patient characteristics suggested that MCP patients showed statistically significantly lower levels across all 4 measures by 10 months postenrollment.

CONCLUSIONS:

Legal access to cannabis may reduce the use of multiple classes of dangerous prescription medications in certain patient populations.