No Opioid Sparing Effect With Cannabis in Chronic Pain

Individuals with chronic pain who used cannabis and opioids likely did not have more pain relief during co-use. These findings were published in the Journal of Pain.

Participants (N=46) with chronic pain were recruited for this study between 2019 and 2020 from the 11 states and Washington DC that had legalized recreational cannabis. Eligible participants had a current prescription for opioid medications, a medical recommendation for cannabis, and a pain severity of 3 or more on a 10-point scale. An ecological momentary assessment (EMA) was conducted for 30 days using a smart phone application which prompted participants to respond to random surveys and daily reports about their opioid and cannabis use and the effect on their chronic pain symptoms.

The study population comprised 78.3% women, aged mean 44.8 (standard deviation [SD], 12.9) years, 93.5% were White, 8.7% had a history of alcohol or drug use problem, and 56.5% reported their chronic pain caused high disability and was severely limiting.

The EMA application sent a total of 6888 prompts, of which 80% were random surveys and 20% were daily diaries. The random prompts were responded to 70% of the time and the daily diaries 92% of the time.

At baseline, the most common opioid regimens included short-acting hydrocodone with paracetamol (45.7%), long-acting oxycodone (19.6%), sort-acting oxycodone (15.2%), and short-acting tramadol (15.5%).

The most common cannabis regimens included high delta-9-tetrahydrocannabinol (THC) marijuana (54.3%), equal THC and cannabidiol (CBD) marijuana (39.1%), high THC cannabis edibles (39.1%), equal THC and CBD cannabis edibles, cannabis concentrates (30.4%), and high THC cannabis oil (30.4%). The most common method of ingestion was via a vaporizer (33.3%), joint (15.6%), other (15.6%), and bong (11.1%).

In the daily diary, 50.0% were co-use days, 30.2% were cannabis only days, 12.2% were opioid use only days, and 7.6% were no use days. There were no reports of using illicit opioids.

Higher perceived pain did not increase the likelihood of co-use in the subsequent occasion. The likelihood of using opioids alone was increased on the basis of pain severity (odds ratio [OR], 1.27; P <.001).

Switching between co-use and single use was common.

Perceived pain relief was highest during co-use (mean, 6.9; SD, 2.0), followed by cannabis only (mean, 5.4; SD, 2.7) and opioids only (mean, 4.5; SD, 2.1). A linear mixed-effects model supported the trend that co-use was superior to cannabis or opioids alone (both P <.001) but did not support the trend that cannabis use was superior to opioid use (P =.683).

A post hoc analysis comparing responses to the momentary random prompts with daily diaries did not support these trends, suggesting that recall bias may have significant impact on perceived pain.

The major limitation of this study was the small sample size.

This study found that co-using cannabis and opioids for chronic pain had increased perceptions of pain relief when patients were asked to recall their previous day pain levels, but that momentary pain assessments did not support the improved analgesic effect of co-use.

Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.