Cannabis and Placebo Similar in Reducing Pain in Sickle Cell Disease Patients

Donald Abrams, MD

Vaporized cannabis did not statistically significantly reduce pain and associated symptoms compared to vaporized placebo in patients with sickle cell disease with chronic pain.

Cannabis was more effective than inhaled placebo in interference in mood.

Donald Abrams, MD, and colleagues aimed to determine whether inhaled cannabis was more effective than inhaled placebo in reliving chronic pain in adults with sickle cell disease. Their findings suggested cannabis should be further investigated in larger and longer clinical trials as an adjunct or alternative to opioids.

The team of investigators conducted a pilot randomized clinical trial with patients with sickle cell disease and chronic pain admitted to a single inpatient clinical research center for 2 separate five-day stays from August 2014 to April 2017. Participants were using a stable pain medication for at least 2 weeks.

Furthermore, all patients enrolled needed to have prior experience smoking cannabis so they knew how to inhale and what neuropsychological effects to expect. Those who were current users were asked to stop any cannabis use for 1 week before study admission. All participants were also required to have prior exposure to cannabidiol (CBD) so they would not be exposed to further risk.

Cannabis and placebo cannabis were obtained through the National Institute on Drug Abuse. The cannabis contained 4.4% tetrahydrocannabinol (THC) and 4.9% CBD. The placebo cannabis had CBD extracted.

A vaporizer called the Volcano was used to inhale the cannabis. The Volcano inflated a bag with vapors after heating the cannabis plant. Participants were encouraged to inhale at least 1 full bag of vapor.

All participants were admitted for 2 inpatient stays of 5 days and 4 nights in the clinical research center. Stays were separated by at least 30 days. During 1 stay, the participants inhaled vaporized cannabis 3 times daily. During the other stay, they inhaled vaporized placebo cannabis on the same schedule. Participants remained on their outpatient analgesic regimen. Additional inpatient analgesics were prescribed as needed for increased pain.

To rate their chronic pain level, the participants scored how they felt on a visual analogue scale from 0-100. Participants rated their pain upon arrival and repeated daily, 2 hours after the morning drug inhalation. On days 1 and 5, participants completed the Brief Pain Inventory.

Abrams and the team included 23 participants in the study. Participants had a mean age of 37.6 years old and more than half (56%) were women.

The mean difference of in pain rating between the cannabis and placebo groups was -5.3 for day 1, -10.9 for day 2, -16.5 for day 3, -8.9 for day 4, and -8.2 for day 5. None of the differences were statistically significant.

There was also no statistically significant mean difference in pain interference ratings between cannabis and placebo between days 1 and 5 for interference during general activities (day 1: .27, day 5: -1), walking (day 1: .14; day 5: -.87), sleep (day 1: .59; day 5: -1.3), or enjoyment (day 1: .23; day 5: -.91). The investigators did report a statistically significant mean difference in decrease in interference with mood (day 1: .96; day 5: -1.4; P=.02).

Overall, cannabis use was well tolerated, and adverse events were mild and equivalent to those reported by placebo recipients. Because cannabis has been shown to be a generally safe intervention and patients with sickle cell disease often use multiple medications, the investigators noted the findings had the potential to encourage and guide future larger and longer investigations into the potential use of cannabis-based interventions in chronic pain.

The study, “Effect of Inhaled Cannabis for Pain in Adults With Sickle Cell Disease,” was published online on JAMA Network Open.