Cannabis preparations have been used medicinally for pain for thousands of years; however, prohibition in the 20th century meant that the vast majority of scientific research into the plant and its derivatives was halted. In more recent years, we have seen a steady increase in cannabis research, as well as a rise in the number of patients interested in cannabis-based medicines as an alternative treatment option.
Evidence suggests that medical cannabis may be useful for the treatment and management of a number of conditions and symptoms; however, pain is consistently reported as the most common reason for medical cannabis use, globally. A number of clinical studies have aimed to assess the pain-relieving potential of cannabis in different types of pain, with some promising results. One recent study has found that medical cannabis may be useful in managing lower back pain.
Current evidence suggests that around 60% of the UK population can expect to experience lower back pain at some point in their lives. This high prevalence, combined with disability and low quality of life associated with the affliction, makes effective treatment and management an important consideration. Common treatments for lower back pain can include cortisone injections, manipulation, physical therapy and even surgery.
An observational open-label study
The current study was carried out by researchers from Rabin Medical Center and The University of Haifa in Israel. Access to medical cannabis has been steadily on the rise in Israel over recent decades. Furthermore, almost three-quarters (74%) of medical cannabis prescriptions granted in January and February 2022 were prescribed to treat chronic neuropathic non-cancer pain (CNNCP). The aim of the study, which has been published in the Rambam Maimonides Medical Journal, was to “investigate the effectiveness of cannabis therapy for alleviating low back pain symptoms.”
Patients with chronic low back pain were recruited for participation in the study. The study design involved two arms: the first saw patients administered a sublingual preparation of CBD-rich cannabis extract for a total of 10 months. Following a one-month wash-out period, the second arm of the study was initiated and participants were given a THC-rich smoked inflorescence (whole dried cannabis flowers) preparation for a further 12 months.
The findings of the study indicated that the CBD extract was not significantly effective at reducing lower back pain. Three of the 24 participants withdrew from the CBD arm of the study due to insufficient pain alleviation. In contrast, the researchers observed significant improvements in patient-reported pain following the implementation of the THC-rich cannabis treatment.
A significant reduction in pain scores
Across the 2-year study period, all participants reported a reduction in pain using a Visual Analog Scale for pain where ‘0’ meant ‘no pain’ and ‘10’ meant ‘worst imaginable pain’. The patient-reported pain score fell from 83.3± 15.4 at month 0 to 39.1±18.5 at 24 months. The majority of this pain reduction was reported during the second treatment arm when participants received a high-THC cannabis preparation.
The research team noted: “Our findings indicate that inhaled THC-rich therapy is more effective than CBD-rich sublingual extract therapy for treating low back pain and that cannabis therapy is safe and effective for chronic low back pain.”
A number of minor adverse events were reported by participants – the most common being “red eyes” – however, no serious side effects were observed. Both CBD and THC were generally well-tolerated by all participants, indicating that medical cannabis can have a favourable benefit to side effect profile for the management of lower back pain.
This finding was in line with previous studies that have assessed medical cannabis treatment for non-cancer pain. A 2022 systematic review concluded that “cannabis was shown to be effective to treat back pain with an acceptable side effect profile.” Furthermore, another 2022 study suggested that THC may be useful in managing pain that was previously resistant to treatment. However, it is consistently recommended that additional research is needed to fully understand the pain-relieving mechanisms of cannabis and its derivatives as well as the implications of long-term use.
While the THC preparation used in this study demonstrated promising potential for the management of lower back pain, the researchers noted that most doctors in Israel (and other countries around the world) tend to favour other preparations. This preference is due to the health implications of smoking cannabis and other plant materials; however, these harms may be alleviated by vaporising cannabis. Nonetheless, the authors of the study recommend that future studies assess the potential of THC-rich sublingual preparations to further develop our understanding of the pain-relieving potential of this cannabinoid.