CADTH is committed to supporting Canada’s health care decision-makers through this challenging and uncertain time.
For evidence, tools, and resources related to COVID-19, visit our COVID-19 Evidence Portal.


Begin main content

The Use of Medical Cannabis with Other Medications: A Review of Safety and Guidelines - An Update

Last updated: September 27, 2019
Project Number: RC1188-000
Product Line: Rapid Response
Research Type: Drug
Report Type: Summary with Critical Appraisal
Result type: Report


  1. What is the clinical evidence regarding the safety of the use of medical cannabis with other medications?
  2. What are the evidence-based guidelines regarding drug interactions between medical cannabis and other medications?

Key Message

Evidence of limited quality from two studies of oral cannabidiol in combination with other antiepileptic drugs indicated that cannabidiol may increase serum levels of clobazam. One of these two studies also found that oral cannabidiol may increase serum levels of eslicarbazepine, topiramate, zonisamide, and rufinamide. This evidence was limited by a high risk of bias and may not be generalizable to the Canadian context. Additionally, only antiepileptic drugs were studied. No evidence-based guidelines surrounding drug interactions with medical cannabis were found.