Skip to Content


Generic Name: interferon beta-1b (in ter FEAR on BAY ta 1b)
Brand Names: Betaseron, Extavia

Medically reviewed by Last updated on Nov 7, 2018.

What is Betaseron?

Betaseron (interferon beta-1b) is made from human proteins. Interferons help the body fight viral infections.

Betaseron is a prescription medicine used to reduce the number of relapses in people with relapsing forms of multiple sclerosis (MS). This includes people who have had their first symptoms of multiple sclerosis and have an MRI consistent with multiple sclerosis.

Betaseron will not cure your MS but may decrease the number of flare-ups of the disease.

Important information

Betaseron may be harmful to an unborn baby, or may cause a miscarriage. Do not use Betaseron if you are pregnant. Tell your doctor if you are pregnant or plan to become pregnant during treatment.

Before using Betaseron, tell your doctor if you are allergic to any drugs, or if you have liver disease, a thyroid disorder, epilepsy or other seizure disorder, a bleeding or blood-clotting disorder, anemia (low red blood cells), or a history of depression or suicidal behavior.

Serious allergic reactions can happen quickly and may happen after your first dose of Betaseron or after you have taken Betaseron many times. Symptoms may include difficulty breathing or swallowing, swelling of the mouth or tongue, rash, itching, or skin bumps.

Some patients using interferon medications have become very depressed or had thoughts of suicide. Stop using Betaseron if you have symptoms of depression (sadness, crying, loss of interest in things you once liked) or if you have any thoughts of hurting yourself.

Before taking this medicine

You should not use Betaseron if you are allergic to interferon beta, albumin, or mannitol.

To make sure Betaseron is safe for you, tell your doctor if you have:

  • liver disease;

  • congestive heart failure;

  • epilepsy or other seizure disorder;

  • a bleeding or blood-clotting disorder, such as hemophilia;

  • a history of low white blood cell (WBC) counts;

  • anemia (lack of red blood cells);

  • a history of depression or suicidal behavior; or

  • if you are allergic to latex.

A small number of pregnant women have had miscarriages while using Betaseron. Do not use Betaseron if you are pregnant. Tell your doctor if you become pregnant during treatment.

It is not known whether interferon beta-1b passes into breast milk or if it could harm a nursing baby. You should not breast-feed while using Betaseron.

Betaseron is made from human plasma (part of the blood) which may contain viruses and other infectious agents. Donated plasma is tested and treated to reduce the risk of it containing infectious agents, but there is still a small possibility it could transmit disease. Talk with your doctor about the risks and benefits of using this medication.

How should I use Betaseron?

Betaseron is injected under the skin once every 48 hours (2 days). You may be shown how to use injections at home. Do not self-inject this medicine if you do not understand how to give the injection and properly dispose of used needles and syringes.

Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not use this medicine in larger or smaller amounts or for longer than recommended.

Read all patient information, medication guides, and instruction sheets provided to you. Ask your doctor or pharmacist if you have any questions.

Betaseron is a powder medicine that must be mixed with a liquid (diluent) before using it. If you are using the injections at home, be sure you understand how to properly mix the medicine.

Store unmixed medicine at room temperature away from moisture and heat.

After mixing Betaseron, store in the refrigerator and use within 3 hours. Do not freeze.

Each single-use vial (bottle) of this medicine is for one use only. Throw away after one use, even if there is still some medicine left in it after injecting your dose.

Your care provider will show you the best places on your body to inject Betaseron. Use a different place each time you give an injection. Do not inject into the same place two times in a row.

You will need frequent blood tests to check your liver function.

Use a disposable needle and syringe only once. Follow any state or local laws about throwing away used needles and syringes. Use a puncture-proof "sharps" disposal container (ask your pharmacist where to get one and how to throw it away). Keep this container out of the reach of children and pets.

Betaseron dosing information

Usual Adult Dose of Betaseron for Multiple Sclerosis:

Initial dose: 0.0625 mg subcutaneously every other day, and increased (in 25% increments) every 2 weeks, over a 6 week period, to maintenance dose
Maintenance dose: 0.25 mg subcutaneously every other day

Schedule for dose titration:
Weeks 1 and 2: 0.0625 mg subcutaneously every other day (25% of recommended dose)
Weeks 3 and 4: 0.125 mg subcutaneously every other day (50% of recommended dose)
Weeks 5 and 6: 0.1875 mg subcutaneously every other day (75% of recommended dose)
Week 7 and beyond: 0.25 mg subcutaneously every other day (100% of recommended dose)

What happens if I miss a dose?

Use the missed dose as soon as you remember. Then wait at least 48 hours before using another injection, and restart your dosing schedule at that time. Do not use more than one injection every 48 hours (2 days).

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while using Betaseron?

Avoid injecting this medicine into skin that is sore, red, or infected.

Drinking alcohol with this medicine can cause serious side effects.

Avoid being near people who are sick or have infections. Tell your doctor at once if you develop signs of infection.

Betaseron side effects

Get emergency medical help if you have signs of an allergic reaction to Betaseron: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Some patients using interferon medicines have become very depressed or had thoughts of suicide. Report any new or worsening symptoms of depression to your doctor, such as: mood or behavior changes, anxiety, trouble sleeping, hallucinations, or if you feel impulsive, hostile, aggressive, or have thoughts about suicide or hurting yourself.

Stop using Betaseron and call your doctor at once if you have:

  • seizure (convulsions);

  • pain, swelling, redness, or skin changes where an injection was given;

  • pale skin, easy bruising, unusual bleeding (nose, mouth, vagina, or rectum), purple or red pinpoint spots under your skin;

  • kidney problems - pain or burning when you urinate, blood in your urine, swelling or rapid weight gain, little or no urination;

  • signs of a serious blood cell disorder - confusion, feeling tired or irritable, stomach pain, bloody diarrhea, vomiting;

  • heart problems - fast heartbeats, shortness of breath (especially when lying down), tight feeling in your chest, swelling in your ankles, rapid weight gain;

  • lupus-like syndrome - joint pain or swelling, shortness of breath, skin rash, numbness, cold feeling or pale appearance of your fingers or toes;

  • liver problems - nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or

  • low white blood cell counts - fever, chills, swollen gums, painful mouth sores, pain when swallowing, skin sores, cold or flu symptoms, cough.

Common Betaseron side effects may include:

  • headache, weakness;

  • sleep problems (insomnia);

  • stomach pain;

  • muscle pain or stiffness;

  • abnormal liver function tests;

  • skin rash;

  • flu symptoms; or

  • skin reaction where the medicine was injected.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Betaseron?

Other drugs may interact with interferon beta-1b, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Betaseron only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.