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Study Finds That the Antibiotic Minocycline May Reduce the Likelihood of Transitioning to Definite Multiple Sclerosis

June 1, 2017

  • Researchers in Canada have published results of a small phase 3 clinical trial showing that minocycline, a relatively inexpensive oral antibiotic commonly used to treat acne, can reduce the likelihood that someone with clinically isolated syndrome (CIS) -- experiencing initial neurological symptoms suggestive of MS -- will go on to develop full-blown multiple sclerosis.
  • Dr. Luanne Metz (University of Calgary) and colleagues across Canada tested minocycline against placebo in 142 people with CIS. After 6 months, those taking twice daily minocycline had a 28% reduced risk of developing definite MS, compared to those taking placebo, and also had reduced disease activity detected on MRI scans. The risk reduction is similar to what has been reported with other disease modifying treatments in CIS trials. These benefits were not sustained at 24 months.
  • In addition to its bacteria-killing action, minocycline has been shown to have anti-inflammatory and neuroprotective properties. The most common side effects were rash, dizziness and tooth discoloration. Minocycline carries several warnings including that it is not to be taken during pregnancy.
  • Additional larger clinical trials are needed to confirm the effectiveness of minocycline in MS and CIS. 
- Read more about this study, including FAQ, from the MS Society of Canada
- Access the paper in the New England Journal of Medicine
- Read more about CIS and FDA-approved therapies to treat it

About Multiple Sclerosis

Multiple sclerosis is an unpredictable disease of the central nervous system. Currently there is no cure. Symptoms vary from person to person and may include disabling fatigue, mobility challenges, cognitive changes, and vision issues. An estimated 1 million people live with MS in the United States. Early diagnosis and treatment are critical to minimize disability. Significant progress is being made to achieve a world free of MS.

About the National Multiple Sclerosis Society

The National MS Society, founded in 1946, is the global leader of a growing movement dedicated to creating a world free of MS. The Society funds cutting-edge research for a cure, drives change through advocacy and provides programs and services to help people affected by MS live their best lives. Connect to learn more and get involved:, Facebook, X, formerly known as Twitter, Instagram, YouTube or 1-800-344-4867.


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