Dr. Caroline MacCallum wants doctors to know that cannabis “isn’t the taboo medicine” they might think it is. Not only has she used it successfully to treat more than 50 conditions, she has also seen how it has helped her patients stop using prescription opioids.
MacCallum, a specialist in complex pain and cannabinoid medicine, is the medical director at Green Leaf Clinic in Langley, where she assesses patients for their eligibility for Canada’s Access to Cannabis for Medical Purposes Regulations program.
Besides being a former pharmacist who has spoken publicly on the subject of the plant’s medical applications since 2015, MacCallum is also a clinical instructor in UBC’s faculty of medicine and pharmaceutical sciences. She will share her expertise at the Cannabis and Hemp Conference and Expo on Sunday (May 7).
At Green Leaf, she prescribes cannabis to treat patients suffering from arthritis, fibromyalgia, glaucoma, leukemia, multiple sclerosis, HIV, soft-tissue injuries, lupus, concussions, migraines, and other autoimmune diseases and conditions related to chronic pain.
A vocal advocate who, along with other physicians, recently wrote to the College of Physicians and Surgeons of British Columbia to challenge its stance on medical cannabis, MacCallum wasn’t always aware of its potential for treatment.
“Before Green Leaf, I worked in a number of pain clinics, and I was so discouraged by how I wasn’t getting the results I was hoping for with my patients,” she told the Straight by phone from a conference in Toronto.
“I realized that these drugs don’t work for everyone, or every condition, and I got to a place where I was challenged by my patients to consider cannabis.”
MacCallum started exploring—albeit hesitantly, given the fact that she’d never learned about the plant in medical school—studies that supported its viability as medicine.
“I found that there is so much out there about cannabis,” she said. “It was something I wanted to pursue... out of desperation, because nothing else was working for my patients.”
Now an expert in the field, MacCallum is working with a number of different groups to create hospital policies so when patients are admitted for care, they’re able to use their cannabis in oil form, on-site. It’s just one of the things she is trying to do to help ensure that cannabis is viewed by medical professionals as legitimate medicine.
When prescribing cannabis, MacCallum looks to Canada’s licensed producers (LPs) for products that are appropriate for each patient.
“Because of my pharmacy background and how sick my patients are, I only work with LPs,” she said.
“I feel like it’s the most regulated product—not that dispensaries don’t have great product, but there’s attention given to things like heavy metals in the water, pesticides, amounts of tetrahydrocannabinol [THC] and cannabidiol [CBD], and standardization as a whole,” she said.
MacCallum said she prefers to prescribe cannabis to her patients in oil form but will supplement with flowers meant to be used with a vaporizer. She doesn’t recommend that patients inhale combustibles.
She isn’t only treating pain: often, patients have to deal with symptom clusters, which can add things like anxiety, depression, nausea, and poor sleep to preexisting conditions.
To treat these, MacCallum likes to use CBD-heavy oils and strains. She stresses that THC isn’t the only cannabinoid with medical value: some CBD strains have been shown to help treat the above conditions while also mitigating some of the euphoria caused by THC, which is something that she said not all her patients enjoy.
Above and beyond its ability to treat both pain and symptoms, MacCallum has seen firsthand how cannabis can help her patients reduce—and, in many cases, eliminate—their reliance on prescription opioids.
“I’m able to taper patients off of these drugs and get them less constipated, less confused, and feeling better,” she said, adding that cannabis also helps in treating the symptoms of opioid withdrawal.
Referencing prepublication results from an extensive survey of Canadian medical-cannabis patients, MacCallum said many patients are able to stop using opioids after cannabis is introduced.
A study written by B.C. expert Philippe Lucas and using data from the survey found that 69 percent of surveyed patients used cannabis as a replacement for prescription drugs. Among patients who reported substituting for opioids specifically, 60 percent of opioids being prescribed were successfully reduced by 100 percent, while 18.4 percent were reduced by 75 percent.
MacCallum said she has seen comparable numbers at Green Leaf, where 90 percent of incoming patients are using opioids. She said one of the biggest impacts for patients is the reduction in side effects when cannabis is substituted for opioids.
“You might feel euphoric or foggy at first, but once you’re a medical user, you don’t feel that way,” she said. “If you have constipation or confusion with perception because of pharmaceuticals, you never get used to that. You have that for life.”
Despite the success that MacCallum’s patients have had, the College of Physicians and Surgeons continues to tell doctors in B.C. that there are “few reliable published studies” that discuss the medical benefits of cannabis. MacCallum, however, said it’s the opposite: the college is the one without the evidence to support its statements.
“I really want the college to hear from more cannabis specialists, because a lot of us have expertise, and we’re willing to give it away for free,” she said.
“If they say it’s because of public health, they’re missing a huge opportunity for us to deal with the opioid issues that we’re having. I firmly believe this is the solution to the opioid crisis, and if I keep yelling loud enough, it will eventually be heard.”
Caroline MacCallum will speak at the Cannabis and Hemp Conference and Expo, which takes place on Saturday and Sunday (May 6 and 7) at AMS Student Nest on UBC’s Point Grey campus.