Description and Brand Names

Drug information provided by: Merative, Micromedex®

US Brand Name

1. Avonex
2. Avonex Pen
3. Rebif
4. Rebif Rebidose
5. Rebif Rebidose Titration Pack

Descriptions

Interferon beta-1a injection is used to treat the relapsing forms of multiple sclerosis (MS), including clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease. This medicine will not cure MS, but it may slow some of the disabling effects and decrease the number of relapses of the disease. Interferons are natural substances that are produced in the body to help fight infections. Interferon beta-1a is a synthetic (man-made) version of these substances.

This medicine is available only with your doctor's prescription.

This product is available in the following dosage forms:

• Solution
• Kit

Before Using

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies have not been performed on the relationship of age to the effects of interferon beta-1a injection in the pediatric population. Safety and efficacy have not been established.

Geriatric

Although appropriate studies on the relationship of age to the effects of interferon beta-1a injection have not been performed in the geriatric population, geriatric-specific problems are not expected to limit the usefulness of interferon beta-1a injection in the elderly. However, elderly patients are more likely to have age-related kidney, liver, or heart problems, which may require caution in patients receiving interferon beta-1a injection.

Breastfeeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Levoketoconazole
• Methotrexate

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Zidovudine

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

• Alcohol abuse, history of or
• Angina (severe chest pain) or
• Autoimmune disorders (eg, autoimmune hepatitis, idiopathic thrombocytopenia) or
• Bone marrow problems (decreased amounts of red or white blood cells in your body), history of or
• Congestive heart failure or
• Depression or mental problems, history of or
• Heart disease (eg, cardiomyopathy) or
• Heart rhythm problems (eg, arrhythmia) or
• Liver disease or
• Seizures or epilepsy, history of or
• Thyroid problems—Use with caution. May make these conditions worse.

• Allergy to human albumin, history of—Should not be used in patients with this condition.

• Infection—May decrease your body's ability to fight an infection.

Proper Use

A nurse or other trained health professional will give you this medicine. You may also be taught how to give your medicine at home. This medicine is given as a shot under your skin (usually in the stomach, back of the upper arm, buttocks, or thighs) or into a muscle (usually in the thigh). A nurse or other trained health professional should watch the first Avonex® injection you give yourself.

If you are injecting interferon beta-1a yourself, use it exactly as directed by your doctor. Do not change your dose or dosing schedule without checking first with your doctor. The exact amount of medicine you need has been carefully worked out. Using too much will increase the risk for side effects, while using too little may not improve your condition.

You will be shown the body areas where this shot can be given. Use a different body area each time you give yourself a shot. Keep track of where you give each shot to make sure you rotate body areas. Do not inject into skin areas that are irritated, reddened, bruised, infected, or scarred in any way.

Check the injection site after 2 hours for redness, swelling, and tenderness.

Use only the brand of this medicine that your doctor prescribed. Different brands may not work the same way.

Rebif® comes as an autoinjector or a prefilled syringe. It works best if you use it at the same time (usually in the late afternoon or evening) on the same 3 days (eg, Monday, Wednesday, and Friday) at least 48 hours apart each week.

Avonex® comes as a prefilled autoinjector pen or a prefilled syringe.

Use a new needle or syringe each time you inject your medicine. Do not use any other needle for the prefilled autoinjector pen.

Each package of medicine contains a Medication Guide and a sheet called Instructions for Use. Read this information carefully and make sure you understand:

• How to prepare the injection.
• How to use disposable syringes or autoinjectors.
• How to store the syringes or autoinjectors.

Allow Avonex® prefilled autoinjector pens and prefilled syringes and Rebif® autoinjector to warm to room temperature before injection by removing from the refrigerator for about 30 minutes. Do not heat them in a microwave oven or in hot water.

You may also receive other medicines (fever medicine, pain medicine) to help prevent or lessen flu-like symptoms (eg, fever, cough, chills, body aches) that may occur during treatment with this medicine.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

• For injection dosage form:
  • For multiple sclerosis:
    • Adults—
      • Avonex®: At first, 7.5 micrograms (mcg) injected into a muscle once a week on the same day (eg, every Monday at bedtime). Your doctor will increase your dose by 7.5 mcg each week for the next 3 weeks until you reach 30 mcg weekly.
      • Rebif®: At first, 4.4 or 8.8 mcg injected under the skin 3 times a week. Your doctor will adjust your dose as needed.
    • Children—Use and dose must be determined by your doctor.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Avonex®: If you miss a dose, give it as soon as you can. Go back to your regular schedule the following week. Do not use this medicine 2 days in a row.

Rebif®: If you miss a dose, give it as soon as you can. Skip the next day and give your regular dose 48 hours later. Go back to your regular schedule the following week. Do not use this medicine 2 days in a row.

Storage

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Store in the refrigerator. Do not freeze.

Store prefilled autoinjector pens or prefilled syringes in the refrigerator. Do not freeze. If refrigeration is not available, Rebif® prefilled syringes may be kept for up to 30 days at room temperature, away from heat (temperatures above 77 degrees F) and direct light. Avonex® prefilled autoinjector pens and prefilled syringes may be stored for up to 7 days at room temperature, away from heat (temperatures above 77 degrees F) and direct light.

Put the used needles into a hard, closed container that the needles cannot poke through. Keep this container away from children and pets.

Precautions

It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly. Blood tests may be needed to check for unwanted effects.

This medicine may cause some people to be anxious, irritable, or display other abnormal behaviors. It may also cause some people to have suicidal thoughts and tendencies or to become more depressed. If you or your caregiver notice any of these side effects, tell your doctor right away.

Check with your doctor right away if you have dark urine, persistent loss of appetite, flu-like symptoms, headache, continuing vomiting, general feeling of tiredness or weakness, light-colored stools, right upper stomach pain or tenderness, or yellow eyes or skin. These could be symptoms of a serious liver problem.

This medicine may cause serious allergic reactions, including anaphylaxis, which can be life-threatening and requires immediate medical attention. Call your doctor right away if you have a rash, itching, hoarseness, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth while you are using this medicine.

This medicine may lower the number of white blood cells in the blood. This will increase your chance of getting an infection. It can also lower the number of platelets in the blood. Platelets are necessary for proper blood clotting. If this occurs, there are certain precautions you can take, especially when your blood count is low, to reduce the risk of infection or bleeding:

• If you can, avoid people with infections. Check with your doctor immediately if you think you are getting an infection or if you get a fever or chills, cough or hoarseness, lower back or side pain, or painful or difficult urination.
• Check with your doctor immediately if you notice any unusual bleeding or bruising, black, tarry stools, blood in the urine or stools, or pinpoint red spots on your skin.
• Be careful when using a regular toothbrush, dental floss, or toothpick. Your medical doctor, dentist, or nurse may recommend other ways to clean your teeth and gums. Check with your medical doctor before having any dental work done.
• Do not touch your eyes or the inside of your nose unless you have just washed your hands and have not touched anything else in the meantime.
• Be careful not to cut yourself when you are using sharp objects, such as a safety razor or fingernail or toenail cutters.
• Avoid contact sports or other situations where bruising or injury could occur.

This medicine may cause redness, pain, or swelling at the injection site. Some patients have developed serious skin infection or damage (necrosis), including a permanent depression under the skin at the injection site. Contact your doctor right away if you notice depressed or indented skin, blue-green to black skin discoloration, or pain, redness, or sloughing (peeling) of the skin.

This medicine commonly causes a flu-like reaction, with aching muscles, chills, fever, headaches, joint pain, and nausea. Using your shot at bedtime may allow you to sleep through the symptoms. Your doctor may want you to take a medicine to help control the pain or fever (eg, acetaminophen or ibuprofen). Carefully follow your doctor's instructions about how to prevent or treat these symptoms.

Thrombotic microangiopathy, including thrombotic thrombocytopenic purpura and hemolytic uremic syndrome may occur while you are using this medicine. Tell your doctor right away if you have black, tarry stools, blood in the urine, difficulty with speaking, fever, pinpoint red spots on the skin, seizures, stomach pain, unusual bleeding or bruising, or yellow eyes or skin.

This medicine may cause pulmonary arterial hypertension (high blood pressure in the lungs). Check with your doctor right away if you have trouble breathing or unusual tiredness or weakness.

This medicine contains albumin, which comes from human blood. Some human blood products have transmitted certain viruses to people who have received them, although the risk is low. Human donors and donated blood are both tested for viruses to keep the transmission risk low. Talk with your doctor about this risk if you are concerned. The Avonex® prefilled autoinjector pen and prefilled syringe do not contain albumin which comes from donated human blood.

The tip cap of the Avonex® prefilled syringe contains dry natural rubber (a derivative of latex), which may cause allergic reactions in people who are sensitive to latex. Tell your doctor if you have a latex allergy before you start using this medicine.

Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

1. Black, tarry stools
2. chest pain
3. chills
4. cough
5. diarrhea
6. fever
7. flu-like symptoms
8. headache
9. joint pain
10. muscle aches
11. nausea
12. pain
13. painful or difficult urination
14. sores, ulcers, or white spots on the lips or in the mouth
15. swollen glands
16. trouble breathing
17. unusual bleeding or bruising
18. unusual tiredness or weakness

Less common

1. Clumsiness or unsteadiness
2. decreased hearing
3. difficulty with swallowing
4. dizziness
5. fainting
6. feeling of warmth
7. hives or itching
8. mood changes, especially with thoughts of suicide
9. muscle spasms
10. pain or discharge from the vagina
11. pelvic discomfort, aching, or heaviness
12. redness of the face, neck, arms, and occasionally, upper chest
13. redness, swelling, or tenderness at the injection site
14. runny or stuffy nose
15. seizures
16. skin lesions
17. sneezing
18. sore throat
19. speech problems
20. stomach pain
21. swelling of the face, lips, or eyelids

Rare

1. Earache
2. general feeling of discomfort or illness
3. loss of appetite
4. painful blisters on trunk of the body
5. painful cold sores or blisters on the lips, nose, eyes, or genitals

Incidence not known

1. Bleeding gums
2. blue-green to black skin discoloration
3. blood in the urine or stools
4. bloody nose
5. chest discomfort or tightness
6. confusion
7. constipation
8. dark urine
9. decreased urine output
10. depressed mood
11. dilated neck veins
12. dry skin and hair
13. fast, irregular, or pounding heartbeat
14. feeling cold
15. general tiredness and weakness
16. hair loss
17. heavier menstrual periods
18. high fever
19. irregular breathing
20. light-colored stools
21. loss of bladder control
22. mental depression
23. mood or other mental changes
24. muscle cramps and stiffness
25. nausea or vomiting
26. nervousness
27. pain, redness, or sloughing of skin at the place of injection
28. pale skin
29. persistent loss of appetite
30. pinpoint red spots on the skin
31. puffiness or swelling of the eyelids, or around the eyes, face, lips, or tongue
32. redness, blistering, peeling, or loosening of the skin
33. sensitivity to heat
34. skin rash
35. slowed heartbeat
36. sudden loss of consciousness
37. sweating
38. swelling of the face, fingers, feet, or lower legs
39. swelling of the mouth or throat
40. throat tightness
41. upper right stomach pain or tenderness
42. weight gain or loss
43. yellow eyes and skin

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

1. Heartburn
2. indigestion
3. sour stomach

Less common

1. Hair loss
2. trouble sleeping

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Portions of this document last updated: Feb. 01, 2024

Original article: https://www.mayoclinic.org/drugs-supplements/interferon-beta-1a-intramuscular-route-subcutaneous-route/precautions/drg-20064352