Using natalizumab may increase the risk that you will develop progressive multifocal leukoencephalopathy (PML; a rare infection of the brain that cannot be treated, prevented, or cured and that usually causes death or severe disability).

Tell your doctor if you have or have ever had PML, an organ transplant or another condition that affects your immune system such as human immunodeficiency syndrome (HIV), acquired immunodeficiency syndrome (AIDS), leukemia (cancer that causes too many blood cells to be produced and released into the bloodstream), or lymphoma (cancer that develops in the cells of the immune system). Also tell your doctor if you are taking any other medications that affect the immune system such as azathioprine (Imuran); cyclosporine (Neoral, Sandimmune); medications for cancer; other medications for multiple sclerosis (MS, a disease in which the nerves do not function properly and patients may experience weakness, numbness, loss of muscle coordination and problems with vision, speech and bladder control) including cyclophosphamide (Cytoxan), interferon beta (Avonex, Betaseron, Rebif), glatiramer (Copaxone), and mitoxantrone (Novantrone); methotrexate (Rheumatrex); sirolimus (Rapamune); and tacrolimus (Prograf). Your doctor may tell you that you should not use natalizumab.

Talk to your doctor about the risks of using natalizumab. Tell your doctor about all the other treatments you have used to control your multiple sclerosis. Your doctor will probably not prescribe natalizumab unless you have not been helped enough by other treatments for multiple sclerosis or you cannot use other treatments.

You will probably need to have a magnetic resonance imaging scan (MRI; a scan that shows pictures of the inside of the body) before you begin treatment with natalizumab.

A program called the TOUCH program has been set up to help manage the risks of natalizumab treatment. You can only receive natalizumab if you are registered with the TOUCH program, if natalizumab is prescribed for you by a doctor who is registered with the program, and if you receive the medication at an infusion center that is registered with the program. Your doctor will give you more information about the program, will have you sign an enrollment form, and will answer any questions you have about the program and your treatment with natalizumab.

As part of the TOUCH program, your doctor or nurse will give you a copy of the Medication Guide before you begin treatment with natalizumab and before you receive each infusion. Read this information very carefully each time you receive it and ask your doctor or nurse if you have any questions.

Also as part of the TOUCH program, your doctor will need to see you every 3 months at the beginning of your treatment and then at least every 6 months to decide whether you should continue using natalizumab. You will also need to answer some questions before you receive each infusion to be sure that natalizumab is still right for you

Call your doctor immediately if you develop any new or worsening medical problems during your treatment. Be especially sure to call your doctor if you experience any changes in your thinking, balance, eyesight, or strength that last several days.

Tell all the doctors who treat you that you are using natalizumab.

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