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What Are the Most Common Natalizumab Side Effects?

Autumn Rivers
Autumn Rivers

The uses of natalizumab usually include treatment of symptoms of multiple sclerosis and Crohn's disease. Though this medication tends to work well for many people, some patients experience a few side effects. For example, a headache, stomach pain and joint swelling are some bothersome side effects that may appear. Some natalizumab side effects affect the mental state and may lead to depression, while a painful or missed period is a side effect that females may experience. Though these should all be mentioned to a doctor as soon as possible, certain natalizumab side effects — including difficulty breathing, fever and vomiting — call for immediate treatment.

As with many medications, natalizumab may bring on some side effects that are more irritating than life-threatening, so patients can often wait until their next doctor appointment to mention them. For example, some people notice swelling and pain in the joints and extremities, such as the hands and feet. Headaches, night sweats and tooth pain also may occur. Many natalizumab side effects mostly affect the stomach area, with constipation, diarrhea and stomach pain, as well as heartburn, all having been reported. Though these all tend to be mild or completely disappear once the body gets used to the medication, these side effects should be mentioned to a doctor if they become worse or begin negatively affecting life.


Some natalizumab side effects are only found in females, with severe menstrual cramps being one issue. Women also may find that their menstrual period becomes irregular or goes missing completely, in which case they should see a doctor to rule out other causes. Women also are encouraged to see their doctor if they notice white discharge from the vagina or a swollen, burning feeling in the area. Both men and women taking natalizumab may experience an increase in the urgency to urinate, and it may hurt when they try to go. Another natalizumab side effect that tends to affect both males and females is depression, which should be mentioned to a doctor so it can be treated.

Patients may develop an infection when taking this drug, and this could be indicated by a sore throat, fever and general flu symptoms. Though these natalizumab side effects may not seem serious, they should be reported to a doctor right away, as should an increase in bleeding or bruising in the body. Additionally, patients who experience vomiting, appetite loss and darker urine, along with a yellow tint to the skin and eyes, should get immediate medical treatment. Side effects aside, symptoms of an allergic reaction to this medication include difficulty breathing, a rash and itching, and should be reported to a doctor right away.

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