What Are the Side Effects of MS Treatments?

You want to find the multiple sclerosis treatment that's right for you, so you’re weighing the benefits and side effects. It starts by getting to know what each MS drug does.

"All of these medications, in one way or another, affect the immune system," says Thomas P. Leist, MD, director of the Jefferson Comprehensive Multiple Sclerosis Center in Philadelphia. "But they are all very different. Some are easier to take than others, some have a more proven safety record, and some are not suitable for certain patients."

If you know what to expect, you'll be better prepared to make decisions about your medicines.

Do-It-Yourself Shots

If your doctor prescribes you an injectable MS drug, you'll give yourself shots into a muscle or under your skin. These were the first medications approved for the disease, and they are considered very safe.

You might get flu-like symptoms -- like muscle and joint pain, chills and fever -- for a day or two after each shot, but it's a normal reaction. Your skin may also be red and irritated near your injection.

"It can happen within seconds to minutes, and it can scare patients a little bit," Leist says. "So we warn people that it's likely to happen, and that the best thing to do is to let it pass."

You might be able to curb these symptoms if you start with a low dose, then slowly increase it over time. Follow the instructions carefully, and keep the skin around the injection site clean. You can take an over-the-counter pain medicine, and an anesthetic cream will help with the discomfort and itching.

Interferon is a drug you can inject on your own. It can affect your liver, so you'll need a blood test every few months. Other side effects include mood disorders or changes in a woman's periods. If you’re depressed, your doctor will check to make sure it doesn’t get worse, Leist says.

You can also try glatiramer acetate (Copaxone),which you need to use every day. If you take this drug, there’s a chance you could lose fat around the area of the injection. This creates a dent in your skin, which is not dangerous but can be permanent.


It can also make you have chest pain, a racing heart, or shortness of breath, but it's not likely. This reaction is rare and if it happens, it’s usually only once or twice. It doesn't seem to be dangerous, but it can be frightening if you don't expect it.

Let your doctor know if it happens. He'll check to make sure the medicine is still OK for you.

Most side effects of injectable drugs go away after a few months, but tell your doctor if they bother you. He may be able to suggest a different drug.

Through Your Vein

You can also get your MS medicine into your system through an IV inserted into your vein. The IV might irritate your skin and cause redness around the needle, but you don’t have to get them very often.

One of the medicines doctors can drip into your system via an IV helps reduce the inflammation of MS. It's called natalizumab(Tysabri). It might give you a headache and some joint pain. It can make you tired, but the fatigue tends to get better on its own. It’s okay to take over-the-counter medicines for pain.

If you have a common and otherwise harmless virus, called the JC virus, this drug can trigger a dangerous brain infection called progressive multifocal leukoencephalopathy (PML). "We deal with that risk by testing patients regularly for the virus," Leist says. "As long as they don't have the virus, they can't get PML."

Alemtuzumab (Lemtrada) is another IV drug you can use to treat relapsing forms of MS. If you take this, you might have more side effects -- including rash, nausea, fatigue, and pain -- than with other MS medicines. You’re more likely to get infections and immune system problems. Because of these safety issues, doctors will have you try at least two other medications before this.

Take Your Pills

Some MS drugs come as pills. You can’t take them if you are pregnant or planning to get pregnant. “They get through the placenta early in a pregnancy and can affect a baby's organ growth,” Leist says. Other side effects include diarrhea, stomach pain, and nausea.


Your doctor might prescribe dimethyl fumarate (Tecfidera), a pill that can help with the inflammation and nerve damage of MS. It might make you flush in the face, make your skin itch, or start a rash. In very rare cases it’s been linked to PML.

Another pill, teriflunomide (Aubagio), targets specific immune cells that are related to MS. This also makes you more vulnerable to illnesses like the flu. It can also cause hair loss, liver problems, and a tingling sensation that may be a symptom of nerve damage.

If you take fingolimod (Gilenya), your doctor’s team will check on you for 6 hours after your first dose, to make sure it doesn’t lower your heart rate when your first take it. It can also lower your white blood cell count, so you should have a blood test before you start taking it. Watch out for chest pain, headaches, nausea, stomach pain, and depression.

When in Doubt, Ask Your Doctor

Speak up if you have a side effect that bothers you. "If something is not right, ask your doctor," Leist says. Together, you can decide on your next steps, whether it's changing your drug, adjusting your dose, or treating the side effect in another way.

MS medications also have support hotlines you can call if you're concerned about a reaction or a new symptom that could be drug-related, Leist says.

WebMD Feature Reviewed by Richard Senelick, MD on December 13, 2015



Thomas P. Leist, MD, professor and director, Comprehensive Multiple Sclerosis Center, Thomas Jefferson University.

Medscape Neurology: "Managing the Side Effects of Medications for Multiple Sclerosis."

Florian Thomas, MD, professor of neurology and associate professor of molecular virology, Saint Louis University Medical Center.

National Multiple Sclerosis Society.

Patten, S. Multiple Sclerosis, 2005.

DailyMed (U.S. National Library of Medicine): "GLATOPA- glatiramer acetate injection, solution."

Medscape: "Glatiramer."

Johns Hopkins Medicine: "Treating Multiple Sclerosis."

Chen, Y. New England Journal of Medicine, September 2009.

MedlinePlus: "Mitoxantrone Injection."

Multiple Sclerosis Association of America: "Long-Term Treatments for MS."

MedlinePlus: "Teriflunomide."

FDA: "Medication Guide: Gilenya."

© 2015 WebMD, LLC. All rights reserved.