OA occurs most frequently in the hands, knees and hips, causing pain, swelling and stiffness. In extreme cases, OA can cause reduced function or disability, with patients unable to work or perform daily tasks. Because there is no cure for OA, doctors treat the symptoms of the disease with various therapies, including over-the-counter medications and prescription drugs. Weight loss, increasing activity and physical therapy are also commonly employed therapies. In more severe cases, additional strategies including supportive devices such as canes or crutches can be used, as well as surgical options such as joint replacement.

In a study published last month in the peer-reviewed Journal of Pain & Palliative Care Pharmacotherapy, a team of British researchers notes that the pain associated with osteoarthritis can be disabling and affect quality of life because of “mood disturbance, interference with social relations, and diminished cognitive function.” However, the opioids and non-steroidal anti-inflammatory drugs (NSAIDs) commonly used to treat OA are not appropriate for long-term use because of potentially dangerous side effects.

As a result, the use of medical cannabis treatments is attracting widespread interest among patients and healthcare professionals. In a report on the study, the National Organization for the Reform of Marijuana Laws (NORML) explains that British medical specialists have been allowed to prescribe cannabis-based medicines to patients who have not responded to conventional medications. The researchers investigated the effectiveness of using cannabis-based medicinal products (CBMPs) including flower and oil extracts in a group of OA patients enrolled in the UK Medical Cannabis Registry.

The researchers assessed the change reported by participants using medical cannabis over one year. An analysis of the data revealed that patients reported symptom improvements at one month, three months, six months, and at one year, indicating a sustained improvement of symptoms throughout the study. “Commencement of CBMP treatment was associated with reductions in pain-specific PROMs [patient-reported outcome measures] at all time points in patients with osteoarthritis,” the researchers wrote in the study.

The researchers documented few serious side effects or adverse events (AEs) associated with cannabis experienced by participants in the study. Most reported side effects were mild or moderate, with dry mouth, drowsiness and constipation being the most commonly reported. “AEs were mainly mild or moderate in severity,”  researchers wrote. “Fatigue was the most common AE in this study.” The authors noted several limitations of the research, including the lack of a placebo group to compare results.

Additionally, the “study was subject to significant selection bias because patients received treatment from the same private clinic; hence, inclusion was limited to those who could afford treatment,” among other limitations. Overall, the researchers found that medical cannabis treatments were an effective treatment for OA, with participants in the study reporting reduced pain and better health-related quality of life (HRQoL). Causality could not be established, however, leading the researchers to call for randomized clinical trials (RCTs) investigating the use of cannabis formulations for the treatment of OA.

“These results suggest an improvement in pain-related outcomes for patients with osteoarthritis following the initiation of CBMP treatment. Furthermore, there was an improvement in general HRQoL metrics across the follow-up period. CBMPs also appeared to be well-tolerated at 12-month follow-up,” the researchers wrote, adding, “Hence, this study supports the development of RCTs for CBMP use in osteoarthritis.” Read less