A study found that CBD and THC in a 1:1 ratio might be superior to typical opioid drugs in treating severe and chronic neuropathic back pain. The retrospective analysis of the German Pain e-Registry of the patients who were taking Sativex or opioids between March 2017 and March 2020 shows that Sativex is superior and better tolerated than typical oral long-acting opioids used as an add-on treatment in the cases of severe peripheral neuropathic back pain.
Sativex, also marketed by the name Nabiximols, is a drug derived from extracts of the Cannabis sativa Linnaeus plant, with a 1: 1 mixture of delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) as the main active substances, and is administrated as an oromucosal spray.
The analysis of the German Pain e-Registry, a national web-based pain registry developed on behalf of the German Pain Association, looked into the treatment of 655 patients who were using Nabiximols oromucosal spray and 655 patients treated with oral long-acting opioids (LAO) – namely oxycodone, hydromorphone, and morphine. The results show the substantial potential of the cannabis-based drug in the treatment of neuropathic back pain.
After six months of the treatment, improvement in all parameters was significantly greater in patients treated with Nabixomols than in those treated with LAO, with the greatest improvement observed in overall well-being.
The adverse effects were much more frequent in the group of patients treated with opioids. By the end of the six-month evaluation period, 192 patients (29.3%) treated with Nabiximols and 301 patients (46.0%) treated with LAO analgesics had discontinued the treatment, with the main reasons found to be drug-related adverse events. In patients treated with Nabiximols, 7.9% discontinued the treatment because of side effects, while the percentage of the patients who were using LAO and seized the treatment because of the side effects was 29.3%. Successful treatment as a reason for discontinuation was registered in 13.6% of patients who were using Nabiximols and 8.5% of patients using LAO.
In both groups, the most common adverse effects were gastrointestinal disorders (10.8% vs 53.6%), nervous system disorders (9.8% vs 22.3%), and psychiatric disorders (4.3% vs 16.0%). All of those occurred significantly less frequently in patients treated with Nabiximols than in those treated with LAO.
Neuropathic back pain and opioids
Chronic low back pain is a common disorder. Over 70% of the population in developed countries experience it at some time in their lives, with 82% still having pain one year later. Chronic low back pain is considered to be a mixed pain syndrome combining neuropathic and nociceptive pain mechanisms. The neuropathic component often stays underrecognized and undertreated. It is caused by the lesions within a degenerated disc after prolonged mechanical compression of the nerve root and/or from the effect of inflammatory mediators released by a degenerated disc on nerve fibers. When a patient suffers from low back pain with a neuropathic component, the symptoms are more severe, and there is an increased likelihood and severity of comorbidities like depression and anxiety.
A systematic review of 15 studies shows that opioids may be efficacious for short-term pain relief, but long-term efficacy from 16 weeks onwards stays unclear. Also, substance use disorders are common in patients taking opioids for back pain and aberrant medication-taking behaviors occur in up to 24% of cases.
For this reason, opioids are generally not recommended as first- or second-line therapy or for long-term treatment of neuropathic low back pain. However, their prescription remains common in daily practice.
Cannabinoids for neuropathic back pain
In preclinical studies, cannabinoids have been shown to exert potential in the treatment of neuropathic pain. The randomized controlled trials of Nabiximols in patients with neuropathic pain deriving from multiple sclerosis, spinal cord injury, allodynia, and brachial plexus injury suggested benefits in bringing pain relief.
In Europe and other countries, Nabiximols or Sativex oromucosal spray is indicated for symptom improvement in patients with moderate to severe spasticity due to multiple sclerosis who have not responded adequately to other medication. In Germany, since March 2017, physicians have been permitted to prescribe medical cannabis products for on- or off-label use in patients with severe disease resistant to available therapeutic options. A published exploratory analysis of anonymized 12-week data from the German Pain e-Registry database for 800 adults treated in clinical practice with add-on Nabiximols oromucosal spray for severe chronic pain suggested the drug is particularly effective for the treatment of neuropathic pain. The present study confirmed those findings. Now, a large well-designed prospective randomized controlled trial is needed to confirm the effectiveness and tolerability of Nabiximols or Sativex oromucosal spray in patients with neuropathic back pain.
CBD for opioid addiction
Opioids, including opiates (heroin and opium), pharmaceuticals, and other synthetic opioids, present a major health concern because of the severe consequences associated with their use. In Canada, opioid overdose deaths increased by 50 percent in two years, from 3,023 deaths in 2016 to 4,398 deaths in 2018, the majority of them involving the powerful opioid fentanyl. The EMCDDA European Drug Report 2020 shows that opioids are found in 82% of fatal overdoses, with around 1.3 million high-risk users.
There are some findings that show the potential of CBD not only as a replacement for opioid therapy but also as a drug that could help ease the symptoms of opioid addiction. A clinical trial on 42 participants has found that CBD efficiently reduces cravings and anxiety in abstinents with heroin use disorder. The effects are seen even after the very first dose and last longer than the presence of CBD in the body. These findings can present a turning point in the fight against the global opioid crisis.