Inhaled cannabis fails to significantly reduce chronic sickle cell disease pain
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Vaporized cannabis did not significantly reduce chronic pain and most associated symptoms compared with placebo among adults with sickle cell disease, according to results of a randomized study published in JAMA Network Open.
“Opiates remain the mainstay of analgesics for sickle cell-related pain, often with nonsteroidal anti-inflammatory agents,” Donald Abrams, MD, professor in the department of medicine and integrative oncologist at University of California, San Francisco, told Healio. “Our study was small and short. If you look at the results, everything favors cannabis over placebo, but statistical significance was not achieved.”
Cannabis is legally available for medical use in 33 states and the District of Columbia and is obtained from dispensaries across the U.S. primarily for pain relief. However, few data exist from controlled human trials to support widespread medicinal use of cannabis for painful conditions, including sickle cell disease.
Although some therapies have shown efficacy in treating or preventing vaso-occlusive crises among patients with sickle cell disease, treatments for chronic pain — aside from opioids — have not been rigorously investigated.
Abrams and colleagues sought to evaluate the effect of inhaled cannabis vs. inhaled placebo for chronic pain relief among 23 patients (mean age 37.6 years; 56% women; 91.3% Black) with hemoglobin SS and chronic sickle cell disease-related pain. All participants had been on a stable pain medication regimen for at least 2 weeks and all had previous experience smoking cannabis.
Researchers randomly assigned participants to vaporized cannabis plant material containing 4.4% delta-9-tetrahydrocannabinol (THC) and 4.9% cannabidiol (CBD) or placebo cannabis, inhaled three times a day for 5 days.
Researchers assessed pain and pain interference ratings during each 5-day period using the Brief Pain Inventory. Patients reported their pain on a visual analogue scale, with scores of 0 to 100, on arrival and 2 hours after morning drug inhalation each day.
Daily pain served as the study’s main outcome.
Results showed a mean difference in pain rating assessment between the cannabis and placebo groups of 5.3 (8.1) for day 1, 10.9 (7) for day 2, 16.5 (9.2) for day 3, 8.9 (6.7) for day 4, and 8.2 (8.1) for day 5. None of these differences reached statistical significance.
Researchers observed no statistically significant mean differences in pain interference ratings between cannabis and placebo for interference in general activities (day 1, 0.27 [0.35]; day 5, 1 [0.5]), walking (day 1, 0.14 [0.73]; day 5, 0.87 [0.63]), sleep (day 1, 0.59 [0.74]; day 5, 1.3 [0.8]), or enjoyment (day 1, 0.23 [0.69]; day 5, 0.91 [0.48]). However, researchers did observe a significant mean difference in decrease in interference with mood (day 1, 0.96 [0.59]; day 5: 1.4 [0.6]; P = .02).
The cannabis appeared well-tolerated, with mild adverse events equivalent to those reported by the placebo group.
“Whether the 1:1 ratio THC:CBD cannabis we used in this trial was more or less effective than a THC-dominant variety is unknown,” Abrams said. “Ideally, it would have been preferable to investigate a THC-dominant and a CBD-dominant strain in addition to the 1:1 and placebo to get the best understanding of what may best assist this population.”
For more information:
Donald Abrams, MD, can be reached at donald.abrams@ucsf.edu.
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