First do no harm: Start low, go slow
While these findings provide a rationale for medical cannabis in chronic pain, exploring options with patients can be challenging. Studies on medical cannabis consistently note that patients want information, but data also show that many providers express a lack of knowledge to provide adequate counseling.
There are also legal hurdles. Despite the authorization of medicinal cannabis across a majority of states and territories, cannabis is still a schedule I substance under the Federal Controlled Substances Act. In addition, the absence of standards around formulations, potency, and dosing has also been cited as a major barrier to recommending medical cannabis, as have concerns about adverse events (AEs), especially with inhaled and tetrahydrocannabinol (THC)-predominant formulations.
Like most medications, medical cannabis dosing should be individualized depending on product, patient, and ability to titrate the dose, but the guidelines provide a general rule of thumb. Providers considering therapeutic noninhaled medical cannabis trials are encouraged to start with a low-dose cannabidiol (CBD) oral tablet, spray, or sublingual oil drops 5 mg twice daily, increasing it by 10 mg every 2-3 days depending on the clinical response (to a maximum daily dose of 40 mg/day). If patient response is unsatisfactory, they should consider adding 1-2.5 mg THC/daily, titrated every 2-7 days to a maximum of 40 mg/day.
Still, an important caveat is whether or not adjunctive CBD alone is effective for chronic pain.
Dr. Ziva Cooper
Dr. Ziva Cooper
“While we know that one out of seven U.S. adults are using cannabidiol, we know very little about its therapeutic effects when given by itself for pain,” Ziva Cooper, PhD, director of the Cannabis Research Initiative at the University of California, Los Angeles, and an associate professor at-large of psychology and behavioral science, said in an interview. (Dr. Cooper was not involved in the guideline development.)
“But patients tend to self-report that CBD is helpful, and at low doses, we know that it is unlikely to have adverse effects of any significant concern,” Dr. Cooper noted.
Depending on its components, medical cannabis is associated with a wide range of AEs. Studies comprising the evidence base for the guideline reported transient cognitive impairment (relative risk, 2.39; 95% CI, 1.06-5.38), vomiting (RR, 1.46; 95% CI, 1.07-1.99), and drowsiness (RR, 2.14; 95% CI, 1.55-2.95), attention impairment (RR, 4.04; 95% CI, 1.67-9.74), and nausea (RR, 1.59; 95% CI, 1.28-1.99). Of note, findings of a subgroup analysis showed that the risk of dizziness increased with treatment duration, starting at 3 months (test of interaction P = .002).
However, Dr. Cooper explained that, because the included studies were inconsistent in terms of cannabis type (e.g., some looked at synthetic THC or THC-like substances where others looked at a THC/CBD combination) and formulation (capsules, oral mucosal sprays), it’s difficult to tease out component-specific AEs.
“These are really important things to note, especially when you think about different populations that might be using these types of medicines moving forward,” she said.
Toward that end, the guideline specifically states that there is “no reason why the expected benefits would be systematically different among adolescents and emerging adults.”
Among children with cancer, prior study findings reinforce the conclusion that benefits are similar to adults, but studies in this area are limited to end-of-life treatment, childhood cancer with primarily palliative intent, or progressive or relapsed cancer. Because THC’s safety profile is less certain in children, it’s also important to consider adverse neurocognitive effects before initiating a medical cannabis trial in this population.