Dr. Susan Fox, Professor
Associate Director, Movement Disorders Clinic
Toronto Western Hospital
University of Toronto
Garden Centre Group Co-Op Corp. Pilot Project Grant
Pilot Project Grant
$44,925 over 1 year

Cannabinoids for Pain in Parkinson’s disease

Pain is a constant companion for as many as 10 percent of people with Parkinson’s disease. Unfortunately, most of them can’t tolerate the sleepiness and confusion regular pain medications induce.

That’s why Dr. Susan Fox, a Toronto neurologist and professor at the University of Toronto, is investigating a different source of pain relief. Fox is conducting a pilot study, along with her colleague Dr Tiago Mestre in Ottawa, to see whether 15 people with Parkinson’s disease will benefit from oils made from cannabinoids – the active compounds in marijuana.

Currently, people with Parkinson’s may experience pain in their muscles and joints because of the stiffness and rigidity the illness causes. Some also report a sharp pain, often in their legs or feet, that is more puzzling because doctors can’t determine its exact cause.

“Some people call it central pain,” says Fox. “It’s probably mediated by some brain mechanism reflective of Parkinson’s. People express this as an unpleasant burning, stabbing pain, and it’s very difficult to treat.”

Fox, who treats people with Parkinson’s at Toronto Western Hospital’s Movement Disorders Clinic, hopes her study will discover whether people with Parkinson’s can tolerate oils, and experience less pain after using them. She also wants to identify the best strength and dosage for people to use.

Almost every day, one of her patients asks her about trying marijuana to relieve their tremors or rigidity.

But although marijuana might help people relax and feel less rigid temporarily, there’s no evidence that it relieves those symptoms long-term, she says.

“There’s always this misconception that cannabis can help anything and everything,” she adds.

Fox would rather see her patients try approved and safe medications to relieve tremors and rigidity, so that’s why   this study is focused on determining if there is any benefit of  cannabis oils to treat pain..

Fox’s study will also assess whether these oils cause drowsiness and lower blood pressure – already a concern for people with Parkinson’s. There is also a small risk the oil could induce or worsen hallucinations – a symptom some people are already experiencing.

If Fox’s research demonstrates that people can tolerate cannabis oil and it doesn’t have worrisome side-effects, then her results could lead to a larger, randomized controlled trial.

“There are clear risks and side effects with cannabis, so you weigh up the risk versus the benefit ratio,” she says.

Most importantly, Fox hopes the cannabis oil will not only help people with Parkinson’s feel better, it will also relieve a burden for their caregivers.

“It’s an unmet need,” she says. “It’s very challenging for the family, as well, to watch their loved one in pain and agony.”