Modified: February 1, 2023


Dear @Name@,

Your healthcare team has discussed the following subject with you: natalizumab. The brand name is Tysabri. Here is some additional information. Let us know if you have any questions regarding this information.

How it works: This medication belongs to a class of drugs called biologics. It helps to reduce irritation and swelling (inflammation) in the intestines. In some cases, this medication is used by itself. In other cases, this medication is used together with another medication to achieve better results. This medication is also considered an integrin receptor antagonist.

How it is taken: It is injected into a vein in a procedure called an infusion. The infusion is given at a certified infusion center and lasts approximately 1 hour. Your healthcare team may adjust the dose and how often you receive it, but typically it is given once every 4 weeks.

Possible side effects: Side effects can include urinary tract infections, upper respiratory infections, headache, tiredness, depression, joint pain, diarrhea, and stomach pain.

Special considerations: It carries an increased risk of a severe brain condition called progressive multifocal leukoencephalopathy (PML), which can be caused by the John Cunningham (JC) virus. It is important to be tested for JC virus prior to starting this medication. Patients who are negative for the JC virus have a much lower risk of developing PML. 

Monitoring: Be sure to get tested for tuberculosis and Hepatitis B before taking this medication. Your provider may check routine labs like blood count, liver enzymes, kidney function and inflammatory markers while on this medication.

Points to remember: Before taking this medication, let your healthcare team know about other medical conditions that you may have or other medications (even over-the-counter medications or complementary therapies) you may be taking.

Other tips: The best way to control your disease is by taking your medication as directed. Even when you do not have any symptoms, it is very important to continue taking your medication to prevent your disease from becoming active again. Do not alter the amount of the medication or how frequently you take it on your own. If you have any side effects or you continue to have symptoms, speak to your healthcare team immediately.

For further information, please check out or follow this link:


PDF /sites/default/files/2023-10/Biologics%209.2023.pdf