A US study suggests that the availability of medical cannabis hasn’t dented the use of opioids for non-cancer pain.
Access to medical cannabis under state laws in the US has not affected usage rates of opioid and other prescription painkillers in chronic non-cancer pain, according to Weill Cornell Medicine investigators.
Prescriptions for opioid and non-opioid painkillers and procedures for chronic non-cancer pain were considered in 12 states that had implemented medical cannabis laws and 17 comparison states that hadn’t.
They found that during the first three years of laws, there was almost no difference in the observed measures of opioid and non-opioid prescriptions and procedure numbers between states with and without medical cannabis laws.
“Medical cannabis laws had an average estimated effect of less than 0.2 percentage points on the proportion of patients receiving any opioid prescription, non-opioid pain medication prescription, or pain procedure in a given month during the first 3 years of law implementation, with confidence intervals not exceeding a 0.5 percentage point increase or decrease,” wrote the authors in the Annals of Internal Medicine.
The researchers analysed the prescription records of almost 600,000 commercially insured adults with chronic non-cancer pain.
They looked at prescriptions for opioid and guideline-concordant non-opioid pain medication, and pain-relief procedures such as physical therapy. Pain conditions included arthritis, low back pain, serious headache, fibromyalgia and neuropathic pain.
This finding is contrary to what previous studies and patient surveys have suggested and, given the current US opioid crisis, what public health authorities and policymakers may have hoped.
“Some research suggests that perhaps medical cannabis laws reduce opioid prescribing for chronic non-cancer pain because some people may substitute cannabis,” said study lead Dr Beth McGinty in a media release.
“We found no effects of these laws on opioid prescribing or any types of treatment for chronic non-cancer pain that we looked at.
“Policy makers trying to curb excess opioid prescribing and overdoses should focus on other strategies.”
