Background Various jurisdictions have legalised medical cannabis (MC) for use in chronic pain treatment. The objective of this study was to determine if the use of MC is related to a reduction in the use of prescription opioids and other prescription medications and healthcare services.

Methods A retrospective cohort study was conducted using the medical files of 68 Israeli patients with chronic pain using MC. Number of prescription medications filled and healthcare services used were recorded separately for the baseline period (6 months prior to the start of MC treatment) and 6 months’ follow-up. Paired t-tests were used to compare each individual to himself/herself from baseline to follow-up.

Results Patients filled less opioid prescription medication at follow-up compared with baseline, and the reduction was of small effect size. There were no significant changes in the use of other medications or use of healthcare services from pre-MC treatment to follow-up.

Conclusions MC may be related to a significant yet small reduction in opioid prescription medication. Further prospective studies with representative samples are warranted to confirm the potential small opioid-sparing effects of MC treatment, its clinical importance, if any, and potential lack of association with other healthcare-related services and medication use. Due to methodological limitations of the data used in this study, results may be regarded as preliminary and causal inferences cannot be made.