context: Your body makes interferons naturally. Three forms -- alpha, beta, and gamma -- control the activity of your immune system. But doctors also can use a man-made version of these forms to treat MS, especially interferon beta. Interferon beta medications reduce the frequency of exacerbations and stabilize the course of the disease. They might also slow down how quickly symptoms get worse and help people have less physical disability over time. There are five types of interferon beta on the market in the U. S. They're FDA-approved for relapsing forms of MS: Avonex. You take it once a week as a shot into your muscle. People who start taking it in the early stages of multiple sclerosis may be able to go longer before any physical disabilities begin or get worse. Betaseron. This comes as a shot that goes into the layer of fat just under your skin. You'll need it every other day. Extavia. This one also comes as an injection that goes just under the skin every other day. Plegridy. You can take this interferon less often than the other types -- a shot every 2 weeks. The way it's made makes it last longer in your body. Rebif. You get this drug three times per week as an injection under your skin. When you take these medicines, you might have other health problems, such as: Flu-like symptoms, such as fatigue, chills, fever, muscle aches, and sweating during the first weeks of treatment. To keep those from slowing you down, it's best to take the shot at bedtime. You can take pain and fever relievers, like acetaminophen or ibuprofen, before each injection and during the 24 hours after one to help relieve these problems. Swelling, redness, and pain at the place where you get the shot. If the spot gets hard, call your doctor. Don't give yourself another shot into that site. Trouble with your mood. You might feel sadness, anxiety, irritability, guilt, trouble concentrating, confusion, and have a hard time sleeping or eating. Tell your doctor about these symptoms right away. Women who are pregnant, breastfeeding, or trying to get pregnant shouldn't use interferon drugs. When you take them, be sure to use birth control. Since the meds can cause depression or make it worse, people who've had the condition before need to keep an eye on their mood. Let a doctor know about any changes in how you feel. Interferons also can affect your blood cells and how your liver and thyroid gland work. A few people who took Avonex had severe liver injury or liver failure. Your doctor will give you regular blood tests to be sure your body is working as it should. Glatiramer acetate ( Copaxone) is another drug that makes relapses happen less often for people with MS. It's a man-made version of a protein that's part of the protective coating around the nerves in your body. You get it as an injection under your skin three times per week. Doctors don't know exactly how Copaxone works, but it seems to alter the way the immune system behaves. Pain, redness, and swelling where you get the injection. You should change the place where you give yourself the shot each time. Your doctor should give you a schedule that tells you when to pick a new spot. Chest pain or tightness A fast or irregular heartbeat Anxiety Flushing Trouble breathing You shouldn't take the drug if you're pregnant. If you're planning to get pregnant, ask your doctor whether you need to change your medication routine before you try to have a baby. Also ask your doctor if it's safe to take the drug while you're breastfeeding.