Side effects of multiple sclerosis medications

Disease-modifying medications for multiple sclerosis (MS) can have significant side effects.

Interferon beta

Side effects of treatment with interferon beta-1a (Avonex and Rebif) and interferon beta-1b (Betaseron) may include:

• Flu-like symptoms (such as fatigue, chills, fever, and muscle aches) for 1 to 2 days after an injection. These symptoms, which can be debilitating for some people, often stop after 2 to 3 months of treatment. Taking a pain reliever such as ibuprofen or acetaminophen just before and after each injection may help reduce these symptoms.
• Redness, swelling, or tenderness at the injection site. This is more common with Betaseron and Rebif. Taking a nonprescription pain reliever just before or after an injection can reduce this side effect.
• Depression, anxiety, confusion, and eating and sleeping disturbances. These are not very common and may be related as much to MS as to the treatment. Talk to your doctor if these symptoms last more than a day or two.

Glatiramer acetate

Side effects of glatiramer acetate (Copaxone) may include:

• Pain, redness, or swelling at the injection site (this occurs in most people).
• Flushing.
• Chest pain, rapid heartbeat, and shortness of breath.
• Anxiety.
• Tightness in the throat.

These side effects are rarely serious and usually go away on their own shortly after the injection. You may have one or several brief episodes of these effects during the course of treatment with glatiramer acetate.

Natalizumab

The most common side effect of TNF antagonists, such as natalizumab, is an allergic reaction to the infusion (medicine given in a vein-intravenously, or IV). If you have a reaction to the infusion, it will happen right away, either during the infusion or within 1 to 2 hours after the infusion. Your doctor may give you medicines to prevent or stop the reaction.

Symptoms of an infusion site reaction include:

• Fever.
• Chills.
• Chest pain.
• Shortness of breath.
• Itching (pruritus).
• Headache.
• Nausea.
• Heat and redness (flushing) in the face.
• Rash.
• Fatigue.
• Dizziness.

Warnings about serious side effects of TNF antagonists have been issued. The U.S. Food and Drug Administration (FDA) and the drug’s manufacturers have warned about:

• An increased risk of a serious infection (such as tuberculosis). If you have had tuberculosis (TB) or know someone who has had it, tell your doctor. TNF antagonists also affect your body's ability to fight all infections. So if you get a fever, cold, or the flu while you are taking this medicine, let your doctor know right away.
• An increased risk of blood or nervous system disorders. Call your doctor if you have symptoms of blood disorders (such as bruising or bleeding) or symptoms of nervous system problems (such as numbness, weakness, tingling, or vision problems).
• An increased risk of liver injuries. Call your doctor if your skin starts to look yellow, if you are very tired, or if you have a fever or dark brown urine.

In very few cases, natalizumab has caused a serious and life-threatening disease called PML. Natalizumab is tightly controlled because of this. If you are taking natalizumab, you will be watched closely for signs of any serious side effects.