Cannabis and Cannabinoids for Chronic Pain

Abstract

We found that inhaled (smoked or vaporized) cannabis is consistently effective in reducing chronic non-cancer pain. Oral cannabinoids seem to improve some aspects of chronic pain (sleep and general quality of life), or cancer chronic pain, but they do not seem effective in acute postoperative pain, abdominal chronic pain, or rheumatoid pain. The available literature shows that inhaled cannabis seems to be more tolerable and predictable than oral cannabinoids. Cannabis or cannabinoids are not universally effective for pain. Continued research on cannabis constituents and improving bioavailability for oral cannabinoids is needed. Other aspects of pain management in patients using cannabis require further open discussion: concomitant opioid use, medical vs. recreational cannabis, abuse potential, etc.

Cannabis for Chronic Pain: Challenges and Considerations

“…The report stated that there is substantial evidence that inhaled cannabis is effective for the treatment of chronic pain in adults and moderate evidence that oromucosal cannabinoids (especially nabiximols) improve short‐term sleep disturbances associated with chronic pain (and other conditions such as fibromyalgia, multiple sclerosis, and sleep apnea syndrome) . These conclusions have been supported by other systematic reviews, meta‐analyses, or randomized controlled trials, as we have recently described …”

“…For example, nabilone and dronabinol are pharmaceutical grade THC molecules currently available and approved by the United States Food and Drug Administration (FDA). Similarly, nabiximols, an oromucosal spray preparation that contains virtually equal concentrations of cannabis extracts of THC and CBD, is an investigational drug in the United States (see review article for more details). Surprisingly, and as an unforeseen paradox to modern pharmacy and FDA guidelines and procedures, oral pharmaceutical grade cannabinoids show conflicting results in patients with chronic pain (ranging from not significant to significantly moderate reduction in pain scores over a short term vs placebo) based on moderate‐quality placebo‐controlled trials .…”

“…In addition to their limited efficacy to treat pain, tolerability seems to be a major limitation for clinical use. The number of patients who stop treatment (long term) with oromucosal cannabinoids due to drug‐related adverse events or lack of efficacy is larger than the number of patients observed when using the cannabis plant . This evidence indicates that the tolerability and efficacy profiles of oral cannabinoids are inferior when compared to those of the cannabis plant.…”

“…There is no doubt that their bioavailability is significantly different. The erratic and inconsistent pharmacokinetics (PK) of cannabinoids administered orally (dronabinol, nabilone, or nabiximols) are surely a major determinant for the lack of greater efficacy and reduced tolerability when compared to inhaled cannabis. Development of cannabinoids with improved PK that results in a favorable analgesic profile when given orally is an area of research that should be further supported and explored.…”

Patients’ and clinicians’ perspectives of co-use of cannabis and opioids for chronic non-cancer pain management in primary care

“…Other reviews suggest that inhaled cannabis improves some of the symptoms associated with CNCP. However, these benefits appear to be dependent on dose-response effects as well as the route of administration (Hill, Palastro, Johnson, & Ditre, 2017; Romero-Sandoval, Kolano, & Alvarado-Vázquez, 2017). While randomized control trials have evaluated the efficacy of cannabis, specifically for neuropathic pain, findings need to be interpreted with caution because the lack of appropriate placebo controls may result in an overestimation of benefits (Casarett, 2018).…”