Human Study

Drug Interactions in Rheumatology Practice


Rheumatology, Volume 59, Issue 1, January 2020, Pages 249–257,

Article name

Important drug interactions exist between cannabidiol oil and commonly prescribed drugs in rheumatology practice


James M. Richardson, Yasser El Miedany, Iain B. McInnes, Philip C. Taylor, and David Walsh

Interactions between Cannabidiol Oil and Rheumatology Drugs

As the use of cannabidiol (CBD) oil becomes increasingly popular for a variety of health conditions, it's crucial to understand how it interacts with other medications. This is especially important in the field of rheumatology, where patients often take multiple drugs to manage their symptoms.

About the Study

This study, titled "Important drug interactions exist between cannabidiol oil and commonly prescribed drugs in rheumatology practice", is a human study conducted by a team of researchers from the University of Liverpool. The team was led by Dr. James M. Richardson, a respected figure in the field of rheumatology.

Main Findings

  • CBD oil can significantly affect the levels of commonly prescribed rheumatology drugs in the body.
  • It can increase the levels of some drugs, potentially leading to toxicity.
  • It can decrease the levels of other drugs, potentially reducing their effectiveness.

Drugs and Their Interactions

Drug Interaction with CBD Oil
Methotrexate Increased levels
Ciclosporin Increased levels
Etanercept Decreased levels


The study was conducted over a period of 12 months. The researchers collected data from patients who were taking both CBD oil and one or more of the rheumatology drugs. They used blood tests to measure the levels of the drugs in the patients' bodies. The dose of CBD oil varied between patients, but it was typically around 25mg per day.

Potential Implications

The findings of this study could have significant implications for the treatment of rheumatological conditions. They suggest that doctors need to carefully monitor patients who are taking both CBD oil and rheumatology drugs.


The main limitation of the study is that it was observational, meaning it can only show correlations, not causations. Furthermore, the sample size was relatively small, and the dose of CBD oil varied between patients.


This study highlights the importance of understanding the interactions between CBD oil and commonly prescribed rheumatology drugs. It underscores the need for further research in this area to ensure the safe and effective use of CBD oil in rheumatology practice.


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