Researchers have discovered that an ingredient in common, over-the-counter cough syrups can alleviate symptoms of multiple sclerosis (MS), an inflammatory, autoimmune disease that affects about 2.5 million people worldwide. There are very few effective treatments for MS, which disrupts communication between nerve cells in the brain and spinal cord as the immune system attacks the myelin sheaths that insulate neurons and speed the transmission of nervous signals. But the discovery that the cough medicine chemical dextromethorphan slowed demyelination in mouse models of MS could point to a new MS treatments. "This finding provides an exciting opportunity to better understand the disease and to pursue a new treatment strategy with a drug that is widely available, inexpensive and known to be safe,” Wenbin Deng, author of the study and University of California, Davis, cell biologist, said in a statement.
The study, published online last week (July 7) in Neurobiology of Disease, found that a low dose of dextromethorphan reduced the loss of myelin and paralysis during periods of acute inflammation—which can last weeks or months in humans with MS—in mice with moderate forms of the disease. Deng and his team are studying the benefits of other cough medicine ingredients that, like dextromethorphan, have molecular structures similar to morphine without the toxicity or addictiveness.
"Dextromethorphan has a different mode of action than current drugs for multiple sclerosis," said Deng. "While current treatment targets inflammation and the immune system, dextromethorphan appears to be more directly neuroprotective. Combining the different strategies could offer a real breakthrough in fighting the disease."