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The information on the Sites is intended only to provide knowledge of multiple sclerosis health topics. This information should not be considered complete and should not be used in place of a visit, call, consultation or advice of your physician or other health care provider. Biogen does not recommend the self-management of health problems. Information obtained by using the Sites is not exhaustive and does not cover all ailments, physical conditions or their treatment. Should you have any health care-related questions, please call or see your physician or other health care provider promptly. You should never disregard medical advice or delay in seeking it because of something you have read here.

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Disclaimers for specific site features:

questions to ask your healthcare provider

This section provides some basic questions that you can ask your healthcare provider about multiple sclerosis. The questions contained in this section are intended to provide general consumer information on multiple sclerosis.

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TYSABRI® (natalizumab) is a prescription medicine used to treat adults with relapsing forms of multiple sclerosis (MS) to slow the worsening of symptoms common in people with MS and to decrease the number of flare-ups (relapses). TYSABRI increases the risk of progressive multifocal leukoencephalopathy (PML). When starting and continuing treatment with TYSABRI, it is important to discuss with your doctor whether the expected benefit of TYSABRI is enough to outweigh this risk.

Important Safety Information

TYSABRI increases your risk of getting a rare brain infection—called progressive multifocal leukoencephalopathy (PML)—that usually leads to death or severe disability.

Before receiving TYSABRI, it is important to tell your doctor:
TYSABRI can cause serious side effects. If you have any of the symptoms listed below, call your doctor right away:
The most common side effects of TYSABRI are:
These are not all of the possible side effects of TYSABRI. For more information, ask your doctor. To report side effects to FDA, please call 1-800-FDA-1088.

Please see Full Prescribing Information (PDF) including Boxed Warning and Patient Medication Guide (PDF).

This information is not intended to replace discussions with your healthcare provider.