Intramuscular injections of cannabinoids have been found to be more effective in relieving acute pain compared to oral cannabis treatments, according to a recent systematic review published in Cannabis and Cannabinoid Research. The review, which analyzed six randomized-controlled clinical trials (RCTs), concluded that both types of cannabis treatment resulted in a small but significant reduction in subjective pain scores when compared with placebos in patients experiencing acute pain.
Pain relief is one of the most commonly cited reasons for seeking medical cannabis treatment. However, the clinical evidence supporting the ability of marijuana to reduce acute pain, which is a temporary but distressing pain caused by tissue damage, has been limited. A 2017 review of the available evidence concluded that cannabinoids have no role in managing acute pain based on randomized controlled trials.
Nevertheless, the recent review challenges this verdict to some extent. The authors stated that there is low-quality evidence suggesting that cannabinoids have a small but statistically significant reduction in acute pain in a clinical setting. To reach this conclusion, the authors analyzed six RCTs through a systematic review with a meta-analysis. The trials involved a total of 678 participants, most of whom were recovering from surgery and were given pharmaceutical-grade cannabinoids such as the synthetic THC drug Levonantradol. The authors noted that one trial involving an injection of synthetic THC showed significantly stronger pain-relieving results compared to trials using orally administered cannabinoids like nabilones. This difference is expected because cannabinoids undergo significant first-pass metabolism in the liver, reducing their bioavailability.
During the trials, many participants experienced unpleasant side effects, with those in the cannabinoid groups reporting more cases of nausea, dizziness, and vomiting. However, these side effects were considered nonserious overall, leading the authors to conclude that cannabinoids have a favorable safety profile. The authors also acknowledged certain limitations in the trials, including small sample sizes and variations in dosage, timing, duration, and route of cannabinoid administration. Therefore, further research is needed to determine the optimal route and composition of cannabinoids for acute pain relief, including large-scale randomized clinical trials.
Mike Bennett, a professor of palliative medicine at the University of Leeds, also emphasized the need for more studies on cannabis pain management. In his own review of cannabinoid-cancer pain trials, he found that these medicines were not effective in relieving cancer pain. He suggested that more research using different types of cannabinoid products and outcome measures should be conducted to obtain more certain results.
In conclusion, while intramuscular injections of cannabinoids have shown promise in relieving acute pain, further research is needed to establish their optimal use and efficacy. By conducting large-scale clinical trials with standardized conditions, researchers can better understand the risks and benefits of cannabinoids in managing acute pain and provide evidence-based guidance for healthcare practitioners.
