WEST PALM BEACH, CALIFORNIA — , results from a new phase 3 trial suggested.
The findings from the randomized, placebo-controlled, double-blind study could solve this common problem, known clinically as Uhthoff’s phenomenon, that causes temporary worsening of MS symptoms with heat exposure.
“This could be a game changer,” said study investigator Victoria M. Leavitt, PhD, assistant professor of neuropsychology of Columbia University Irving Medical Center in New York City.
The findings were presented at the annual meeting held by the Americas Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS) and published online in the Journal of Neurology.
A Common Condition
Research suggested that 60%-80% of MS patients experience heat sensitivity. However, while the exact cause is unknown, some evidence suggested it may be related to hypothalamic dysregulation or lesions of the hypothalamus.
Researchers have explored cooling strategies such as liquid-cooled clothing, but available tools can be hard to find, expensive, and cumbersome. Although aspirin has been linked to some symptom improvement in MS, its utility and that of acetaminophen for the condition has not been studied, Dr. Leavitt said.
For the single-center study, researchers recruited 60 patients (81% female; average age, 42 years; 73% White individuals) between 2019 and 2022. Overall, 37 completed at least one study visit, and 29 completed two to three visits. The average disease duration was 6 years.
Participants received oral administration of 650 mg aspirin, acetaminophen, or placebo at each of three study visits over 3 weeks, separated by at least 1 week. At each visit, they took part in a maximal exercise test conducted on a cycle ergometer and were asked to cycle at 50-60 revolutions/min for as long as possible.
Compared with placebo, body temperature increase from baseline to exercise stoppage was significantly reduced with aspirin (0.006 °F vs 0.68 °F; P < .001) and with acetaminophen (0.31 °F vs 0.68 °F; P < .004)
Neither medication was associated with a significant difference in time to exhaustion, and there were no serious adverse events.
“This is really nice because some people might have an adverse reaction to aspirin,” such as gastrointestinal issues. Acetaminophen has a different side-effect profile,” Dr. Leavitt said.
Both medications are inexpensive and available over the counter. The 650-mg acetaminophen dose used in the study is available in an extended-release formula. Typically aspirin isn’t available in doses larger than 325 mg. The 650-mg dose used in the study is considered safe but large.
Dr. Leavitt said she would like to study daily aspirin in people with MS to see if it can boost physical activity. “That’s the test of whether this will meaningfully affect the lives of people with MS,” she said.
No Harm From Overheating
Commenting on the findings, Katherine Knox, MD, associate professor of physical medicine and rehabilitation at the University of Saskatchewan, Canada, noted that “the intervention maybe be initially helpful for the person fearful of getting weaker when they get ‘hot’ with exercise.”
Dr. Knox, who wasn’t involved in the research, added that it’s important for patients with MS to overcome initial barriers and fears about exercise.
“However, for most people the effects of being warm with exercise are less concerning for them after education that the weakness is temporary and does not cause harm if one takes the right precautions such as planning ahead to avoid a fall,” she said. Also, inexpensive interventions such as a fan or a wet cotton headband can be helpful, she said.
The study “provides further evidence that the ‘overheating’ is not causing harm since the time to exhaustion was unchanged,” Dr. Knox added.
The study was funded by the National Institutes of Health. The authors had no disclosures. Disclosure information for Dr. Knox was not available.
A version of this article appeared on Medscape.com.