Less than half of all multiple sclerosis patients take their medication regularly and many stop taking drugs or switch treatments within two years, according to a study released Tuesday.
The research, published in the May edition of the Canadian Journal of Neurological Sciences, raises important questions about problems associated with various MS treatments and what can be done to help patients.
The medications in question are disease-modifying drugs, injected treatments designed to slow the progression of MS.
Paul O'Connor, director of the MS Clinic at St. Michael's Hospital in Toronto and author of the study, noted several reasons why patients don't take their medication regularly or stop treatment.
Most MS drugs are injected, which can be painful and lead to soreness at the injection site. But they also come with a range of side effects, including fatigue and flu-like symptoms, making patients feel worse instead of better, Dr. O'Connor said.
The drugs are also quite pricey, which can be a significant burden on individuals who don't have coverage, he said.
Researchers used data from Ontario's public drug program to determine rates of drug adherence.
They found only 44 per cent of patients involved in the study continually adhered to treatment after a two-year period.
Dr. O'Connor said it's unclear whether patients who stop taking medication fare better or worse in the long term than patients who adhere to their treatments. But there are concerns that patients who stop taking disease-modifying drugs could see an escalated progression in symptoms.
"I tell them that the goal of treatment is not to reverse your disability. I wish that we could do that, but we can't," Dr. O'Connor said. The goal is to stabilize the patient's condition, he added.
The study was funded by the Ontario Ministry of Health and Long-Term Care and the Institute for Clinical Evaluative Sciences. Dr. O'Connor has, in the past, received fees or research support from drug companies for MS trials.