Mode
Text Size
Log in / Sign up

CBD oil shows no surrogate evidence of drug interactions with opioids or benzodiazepines in advanced cancer patientsStudy finds CBD oil did not increase side effects when taken with certain cancer medications

AI-generated summary of the cited source, checked by automated accuracy review. How we work

Key Takeaway
Interpret CBD interaction data cautiously as evidence comes from surrogate measures in a specific trial population.

A randomized controlled trial examined potential drug-drug interactions between CBD oil and concomitant medications in advanced cancer patients participating in the MedCan-1 parent study for symptom control. The study used surrogate measures rather than direct pharmacokinetic assessments, evaluating whether CBD influenced the maximum dose of oil self-selected by patients in relation to specific medication classes, and whether it increased the occurrence of adverse effects when taken with medications of interest.

The main findings showed no evidence from these surrogate measures that CBD increased the likelihood of developing adverse effects or influenced self-selected CBD dose in relation to opioid use or medications including benzodiazepines and antipsychotics. Participants taking paracetamol tolerated higher doses of CBD, though specific effect sizes and absolute numbers were not reported. Safety data including adverse events, serious adverse events, and discontinuations were not reported in the available information.

Key limitations include the use of surrogate measures rather than direct pharmacokinetic or clinical outcome measures of drug interactions. The findings are specific to the context of the parent study for symptom control in advanced cancer patients and short-term use. The discussion suggests concerns about clinically significant drug interactions 'may be unfounded' but this conclusion is based on limited surrogate endpoints. Practice relevance should be interpreted cautiously as the evidence does not establish causation and comes from indirect measures.

Researchers conducted a study to see if CBD oil caused harmful interactions when taken with other medications by advanced cancer patients. The study was part of a larger trial looking at CBD for symptom control. They used indirect measures, like whether patients chose to take more or less CBD or reported new side effects, to check for potential problems.

The study included patients with advanced cancer who were taking various medications, including opioids for pain, benzodiazepines, and antipsychotics. The main finding was that, based on these indirect checks, CBD did not appear to increase the risk of side effects or influence how much CBD patients decided to use when they were also on these drugs. Interestingly, patients who were taking paracetamol (acetaminophen) seemed able to tolerate a higher dose of CBD.

It's very important to understand what this study did not do. It did not directly measure drug levels in the blood to see if CBD changed how other medications worked. The results are based on indirect observations over a short period within a specific clinical trial. No serious safety issues were reported in this analysis, but the methods were limited.

Readers should take from this that early, indirect evidence from one trial suggests CBD may not cause immediate problems when used with some common cancer medications. However, this does not prove it is completely safe for everyone. Patients should always talk to their doctor before starting any new supplement, including CBD, especially when taking other prescription drugs.

What this means for you:
Early, indirect data suggests CBD may not worsen side effects with some cancer drugs, but more direct research is needed.

Study Details

Study typeRct
EvidenceLevel 2
PublishedApr 2026
View Original Abstract ↓
INTRODUCTION: Cannabidiol (CBD) exhibits multiple therapeutic properties, but its use in advanced cancer patients raises concerns about potential drug-drug interactions (DDIs) due to polypharmacy. This study aims to look for evidence of DDIs between concomitant medications and CBD oil in a randomized placebo-controlled trial of CBD oil for symptom control (MedCan-1 parent study). MATERIALS AND METHODS: Surrogate measures were used to identify possible drug interactions: (1) the maximum mL of oil self-selected by patients in CBD or placebo groups in relation to opioids, specific drug groups, or individual agents; (2) the occurrence of any new or worse adverse effect in relation to the study arm and the concomitant medication classes/medications of interest. RESULTS: The dose of CBD self-selected by participants was not related to opioid use or medications, including benzodiazepines and antipsychotics. The likelihood of developing an adverse effect while on study or when taking specific medications was not increased by CBD. Participants on paracetamol tolerated a higher dose of CBD. DISCUSSION: Concerns regarding the development of clinically significant drug interactions when taking CBD in the context of anti-cancer and other concomitant medications at least in the short term may be unfounded.
Free Newsletter

Clinical research that matters. Delivered to your inbox.

Join thousands of clinicians and researchers. No spam, unsubscribe anytime.