Tysabri Side Effects Frequency

Although most people do not experience any problems with

Tysabri^® (natalizumab), certain risks are associated with the use of this drug. Tysabri has been studied extensively in clinical trials. These studies identified the side effects that may occur with Tysabri, as well as the frequency of these problems.

In these studies, the most common side effects of Tysabri included:

Headaches -- in up to 38 percent of people
Fatigue -- up to 27 percent
Respiratory tract infections (such as the common cold) -- up to 22 percent
Urinary tract infection (UTI) -- up to 21 percent
Joint pain -- up to 19 percent.

Some Tysabri side effects are potentially serious and should be reported immediately to your healthcare provider. These include vision problems, fever, or weakness on one side of the body, among other problems.

(To learn more about the frequency of these and other side effects, click Tysabri Side Effects. This article lists other adverse reactions, including symptoms of allergic reactions.)