Cannabis Seen to Help Ease Pain in Sickle Cell Patients in Small Study

David Melamed, PhD avatar

by David Melamed, PhD |

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Cannabis could be a safe and potentially effective way of easing chronic pain in people with sickle cell disease (SCD), according to results of a small clinical trial.

Although the benefits in pain were not statistically significant compared to a placebo, pain interference in mood decreased over the five-day treatment period in participants on cannabis.

Although differences in perceived pain levels were not statistically significant between patients inhaling cannabis or a placebo for five days, pain was less likely to affect mood in those treated. Larger trials into its use as an alternative or add-on to opioids are warranted, the researchers said.

The study, “Effect of Inhaled Cannabis for Pain in Adults With Sickle Cell Disease: A Randomized Clinical Trial,” was published in the journal JAMA Network Open.

Chronic pain, as well as episodes of acute pain caused by a vaso-occlusive crisis, are common complications of SCD.

Opioids are most commonly prescribed treatments for such chronic pain, but they are considered highly addictive. Physicians are also increasingly hesitant to prescribe them as a pain treatment after opioid addiction was acknowledged as a public health crisis in the U.S., with over 100 people per day dying of an overdose in 2018.

Cannabis, which is available for medicinal use in 33 U.S. states and the District of Columbia, has shown potential as a non-addictive means to alleviate chronic pain.

To assess its benefit as a pain treatment, a team led by University of California researchers conducted a clinical trial in patients with hemoglobin SS, the most severe and common form of SCD.  A total of 23 people (mean age, 37.6) completed the trial.

To be eligible, patients had to be taking opioid medications for at least two weeks prior to enrollment. They also had to have experience inhaling cannabis, so they knew how to inhale and what to expect regarding its neuropsychological effects. Current users were asked not to use cannabis for one week prior to the study’s start.

Cannabis used contained 4.4% tetrahydrocannibinol (THC, its main psychoactive cannabinoid) and 4.9% cannabidiol (CBD) as active ingredients, a nearly 1:1 ratio, and was supplied by the National Institute on Drug Abuse.

Patients spent two periods of five nights and four days each in an inpatient clinic, with the two stays separated by at least 30 days. They were allowed to continue their analgesic regimen, with additional painkillers prescribed as needed.

They were randomly assigned either to cannabis in the first period followed by a placebo in the second, or to the inverse order,  enabling patients to be their own controls.

Both cannabis and the placebo were given via a vaporizer device, which the scientists had shown to be an effective method of inhaling cannabis without consuming carbon monoxide and other combustion products. Cannabis and placebo were taken three times each day, at 8 a.m., 2 p.m., and 8 p.m.

Researchers used a scale from 0 to 100 to assess pain levels two hours after the morning treatment. The Brief Pain Inventory was also administered on day one and repeated on day five.

Compared with placebo, treatment with cannabis led to a lower pain level — by 5.3 points on day one, 10.9 on day two, 16.5 on day three, 8.9 on day 4, and 8.2 on day 5. However, these differences were not statistically significant.

Results also found that pain interference with general activities, and with walking, sleeping, enjoyment, and mood all decreased over the five days of cannabis use. But only the decrease in pain interference with mood was statistically significant.

No significant differences were seen in adverse effects between cannabis and a placebo use, or in use of opioids during the treatment periods.

According to the scientists, the small number of participants and the short duration of the study may have contributed to the inability to show lower opioid use among patients on cannabis compared with the placebo group.

“These trial results show that vaporized cannabis appears to be generally safe,” Kalpna Gupta, the study’s senior author, said in press release. “They also suggest that sickle cell patients may be able to mitigate their pain with cannabis.”

“Since no significant adverse effects were observed, this proof of principle study has the potential to encourage and guide future larger and longer investigations into the potential use of cannabis-based interventions in chronic pain that could help to attenuate the ongoing public health crisis related to opioid use,” the investigators wrote.