Medical Cannabis Provides Only Minor Relief for Chronic Pain
/By Pat Anson, PNN Editor
An international team of researchers has concluded that medical cannabis and cannabinoids do not provide relief to most people with chronic pain, but are of some benefit to others.
The findings, based on a limited review of 32 medical cannabis studies, were published in the journal BMJ. They are the third set of international guidelines released this year to discourage the use of cannabis as an analgesic because clinical evidence is lacking.
“We are hopeful that patients and physicians will find our guideline helpful, and take away that while medical cannabis will not be effective for most people living with chronic pain, it may provide important benefits for a minority of patients,” said lead author Jason Busse, associate director of McMaster University’s Medicinal Cannabis Research Center in Ontario, Canada.
“For example, we found that 10% more patients that used medical cannabis vs. placebo in trials reported an important improvement in pain relief. This means that only one patient of every 10 treated with medical cannabis experienced this improvement.”
Busse and his colleagues said medical cannabis might provide a “small increase” in pain relief, sleep quality and physical function, with a “small to very small increase” in side effects such as dizziness, nausea and cognitive impairment.
It’s important to note that the panel’s recommendations do not apply patients in palliative care or to smoked or vaporized cannabis. The research team, which included a diverse group of physicians, academics and patient representatives, could not find a good quality clinical study that explored the use of inhaled cannabis.
“We hope that such trials will be forthcoming, as cross-sectional data has found many (perhaps the majority of) people living with chronic pain who use cannabis therapeutically use dried flower products that are typically inhaled or vaporized,” Busse told PNN in an email.
“The most robust evidence base is probably for use of cannabidiol (CBD) to help manage certain forms of pediatric epilepsy; however, most patients use cannabis to manage chronic pain and there are important evidence gaps that urgently need to be addressed so that patients can make fully-informed decisions.”
Due to the limited research on inhaled cannabis, the guideline’s recommendations only cover cannabis products such as edibles, sprays, oils and tinctures, which are usually low in tetrahydrocannabinol (THC), the psychoactive ingredient in cannabis that makes people high.
The panel recommended that non-inhaled cannabis or CBD only be used on a trial basis by patients when “standard care” for pain management is not sufficient. The recommendation applies to adults and children with moderate to severe chronic pain caused by cancer, neuropathy, nociceptive pain or nociplastic pain. The latter two categories cover conditions such as osteoarthritis and fibromyalgia.
“Our weak recommendation in favour of a trial of medical cannabis or cannabinoids reflects a high value placed on small to very small improvements in self reported pain intensity, physical functioning, and sleep quality, and a willingness to accept a very small to modest risk of mostly self limited and transient harms,” researchers said.
“The panel, including patient partners, believes that there is great variability in how much reduction in pain severity, improvement in physical functioning, or sleep quality each patient would consider important. Patients who place a high value in improving these symptoms by any amount are more likely to pursue a trial of medical cannabis or cannabinoids.”
The researchers recommend that patients start with a low-dose CBD product, and gradually increase the dose and THC level depending on how the patient responds.
Two medical guidelines released earlier this year also take a dim view of cannabis as a pain reliever. The Australian and New Zealand College of Anaesthetists (ANZCA) urged doctors not to prescribe medical cannabis for patients with chronic pain unless they are enrolled in a clinical trial.
The International Association for the Study of Pain also said it could not endorse the use of cannabinoids to treat pain because there was not enough evidence on the safety and efficacy of CBD.
