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Tecfidera is a twice-daily tablet for relapsing MS. It may cause low levels of immune cells, so your doctor will do regular blood tests to check for that. An active ingredient similar to the one in Tecfidera has been linked to four cases of PML. However, this has not been seen in patients taking Tecfidera. The four patients also had additional risk factors for PML. Tecfidera's most common side effects are flushing, stomach pain, diarrhea, nausea, and vomiting.

If these drugs don't work for you, the next step might be to try a different disease-modifying medication called natalizumab (Tysabri). Tysabri prevents immune cells from getting to your brain and spinal cord where they can damage nerves. This drug is used only if other medications fail because it has been linked to PML. If you do take this drug, you will be monitored very carefully while on it. According to the FDA, PML incidence per 1,000 patients is 0.3 cases during the first two months of treatment, 1.5 cases during 25 to 36 months of treatment, and 0.9 during 37 to 48 months of treatment. A blood test can help doctors assess risk for PML. The test looks for evidence of exposure to the JC virus, which causes PML.

In the most severe cases of MS that aren't responding to medication, doctors may prescribe mitoxantrone (Novantrone). This chemotherapy drug, which was originally designed to treat cancer, suppresses the immune system to prevent it from attacking nerve coverings. Novantrone is used sparingly, though, because it carries a FDA “black box” warning of risks of heart damage and a type of leukemia.

Signs of MS Relapse

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