An international review has found a lack of scientific evidence to support the use of cannabis in treating pain.

The appraisal of evidence, carried out by the International Association for the Study of Pain (IASP), is believed to be the largest to date. It looked at all relevant published laboratory and clinical research on the topic of active compounds in cannabis, called cannabinoids, and reducing pain.

Researchers found that although preclinical studies and anecdotal reports from patients support the hypothesis of using medicinal cannabis products to reduce pain, the currently available clinical data does not support this in practice.

Their work is outlined in a series of papers published this month in the journal Pain.

This is not a door closing on the topic, but rather a call for more rigorous and robust research to better understand any potential benefits and harms related to the possible use of medical cannabis, cannabis-based medicines and synthetic cannabinoids for pain relief Professor Andrew Rice Department of Surgery & Cancer

According to the reports, the data on efficacy and safety fail to reach the threshold for the IASP to endorse the general use of cannabinoids for pain control.The authors clarify that the review is limited to using cannabinoids to reduce pain and did not consider the use of cannabinoids for other therapeutic areas – such as reducing spasms in multiple sclerosis.

Professor Andrew Rice, from Imperial’s Department of Surgery & Cancer, and chair of the IASP’s Presidential Task Force on Cannabis and Cannabinoid Analgesia, said: “While the IASP cannot endorse the general use of cannabinoids for treatment of pain at this time, we do not wish to dismiss the lived experiences of people with pain who have found benefit from their use.”

In a position statement, available online, the IASP says that it recognises that some national and regional jurisdictions already permit the use of cannabis and cannabinoids for pain relief, for other medical indications, or for recreational use. But it adds that more research is needed “to elucidate the benefits and harms of therapeutic use of cannabis and cannabinoids for the treatment of pain.”

“This is not a door closing on the topic,” explained Professor Rice, “but rather a call for more rigorous and robust research to better understand any potential benefits and harms related to the possible use of medical cannabis, cannabis-based medicines and synthetic cannabinoids for pain relief, and to ensure the safety of patients and the public through regulatory standards and safeguards.

“The IASP statement is important and timely because we are concerned that in certain jurisdictions medical cannabis may have been introduced without reference to the conventional statutory regulatory procedures for approving marketing of medicines.

“Furthermore, where ‘recreational’ use of cannabis is now permitted, there is a risk that patients could use cannabis for pain relief without the usual safeguard of a medical consultation and monitoring.”

This article is based on materials from the IASP.

The IASP position statement ‘International Association for the Study of Pain presidential task force on cannabis and cannabinoid analgesia position statement’ and full list of papers are published in the journal Pain.