What You Need to Know About Natalizumab (Tysabri)

Natalizumab (Tysabri) is a drug used in the treatment of relapsing forms of multiple sclerosis (MS). We’ve put together a list of things to know about the treatment using information from tysabri.com and the National MS Society.

MORE: Early use of Tecfidera and Tysabri improve MS patients’ outcome according to a study

  • Natalizumab is administered intravenously, usually every 28 days.
  • Patients are monitored for an hour after infusion for any adverse effects.
  • It has been proven to slow the progression of many common MS symptoms.
  • Can decrease the number of MS flares a person suffers.
  • Reduction of relapse rate in the clinical trial was more than 60 percent.
  • Natalizumab works by prohibiting the binding of white blood cells to molecules in the spinal cord and brain, limiting the normal immune response.
  • Natalizumab was approved by the FDA in 2004 after just a year of data from a two-year clinical trial.
  • People who take natalizumab are at a higher risk of developing the rare brain infection, progressive multifocal leukoencephalopathy (PML), and the risk increases the longer you take the drug or if the patient has had the JC virus. Those with other immune-compromising diseases are advised not to take natalizumab.
  • Patients will undergo a risk assessment before beginning the treatment.
  • Regular liver tests are conducted to determine white blood cell counts and check for liver damage.
  • Common side effects include headaches, rashes, fatigue, pains in arms and legs, joint pain, nausea, vomiting, diarrhea, stomach pain, lung infection, nose and throat infections, depression, and vaginitis.
  • Natalizumab is not advised for use during pregnancy or while breastfeeding.

MORE: Tysabri shows long-term safety and efficacy in study of  Japanese RRMS patients 

Multiple Sclerosis News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or another qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.



  1. Dave Kirchner says:

    I was on Tysabri, fantastic, like I was not sick. Had to get off after 2 or so years due to JC virus. Been off for 2 years, on Rituxan, not as good for me. I have asked if your PML level decreases over time so that you can re-start Tysabri treatments. No one can answer. Also appears now that PML is not as lethal and damaging as once was. If true it may be worth re-taking. Any info out there?

    • Martin Halligan says:

      I understand most American adults ARE JC positive. Certainly I am and long have been. I just had Infusion 103 a and will. have 104 next week.

  2. John Singer says:

    You forgot chronic UTIs. I have had 10 UTIs on Tysabri, 8 of which I was hospitalized. A year and a half off this poison, I still get UTIs. Whether it is from the Tysabri still or not… That is subject to debate but, I suspect it is.

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