Older Chronic Pain Patients Starting Medical Cannabis Were More Likely to Later Start Opioids | Research

The takeaway

Opioid-naive older adults prescribed medical cannabis were 54% more likely to initiate long-term opioids the following year.

Geriatricians; pain specialists; medical cannabis prescribers treating older adults.

54% higher risk of opioid initiation after cannabis prescription in older adults

What the researchers found

Among 3,427 opioid-naive patients 66+ with cannabis prescriptions, 1.84/100 person-years initiated 90+ day opioids vs 1.19/100 in 12,006 controls. Adjusted RR: 1.54 (95% CI 1.07-2.23), driven by males (RR 1.82).

Why it matters

This challenges the opioid-sparing narrative. For opioid-naive older adults, cannabis prescriptions were followed by higher opioid initiation rates.

The numbers in context

3,427 vs 12,006 controls. Opioid initiation: 1.84 vs 1.19/100 person-years. RR: 1.54 (1.07-2.23). Males: RR 1.82. Females: RR 1.35 (NS).

How the study worked

Retrospective cohort using Ontario administrative data. 3,427 exposed patients vs 12,006 controls (2014-2019). Inverse probability of treatment weighting.

What this study cannot tell us

Observational. Cannabis patients may have more severe pain. Cannot capture OTC or black market cannabis use in controls.

How to read the evidence

Large retrospective cohort with statistical adjustment, but observational design.

When this study was published

2025 study

The bigger picture

Most opioid-sparing studies look at people already on opioids. This study asks if cannabis prevents future opioid use in naive patients. The answer appears to be no.

Questions still open

Does cannabis fail to control pain in older adults? Is the prescription simply a marker for more severe pain?

Common questions

Doesn't medical cannabis reduce opioid use?

Some studies show it can for people already on opioids. This study found the opposite for opioid-naive older adults starting cannabis.

Why might cannabis users start opioids more often?

Cannabis may have been insufficient for their pain, or seeking cannabis reflects more severe pain that eventually requires opioids.

Read the original research

Opioid Initiation in Older Patients with Chronic Pain Who Received Authorized Cannabis Prescription.

Substance use & misuse, 1-12

View on PubMed ↗Publisher’s paper ↗

Citation

Fontaine, Emilie; El-Mourad, Jihane; Dubois, Cerina; Eurich, Dean T; Dyck, Jason R B; Hanlon, John G; Zongo, Arsene. (2025). Opioid Initiation in Older Patients with Chronic Pain Who Received Authorized Cannabis Prescription.. Substance use & misuse, 1-12. https://doi.org/10.1080/10826084.2025.2586250