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Rebif: 7 things you should know

Medically reviewed by Carmen Fookes, BPharm. Last updated on May 23, 2022.

1. How it works

  • Rebif is a brand (trade) name for interferon beta-1a which may be used to treat certain types of Multiple Sclerosis (MS) in adults.
  • Interferons are cytokines, which are proteins that cells use to communicate with each other to trigger the protective defenses of the immune system in response to viral infections. Interferons also “interfere” with viral replication by protecting cells from viral infections. Interferon beta-1a, the active ingredient in Rebif, is a 166 amino acid glycoprotein that is identical to that of human interferon. Experts aren’t sure exactly how Rebif works for MS but believe it works in the same way as natural interferon, to help control immune system activities, and prevent the immune system from attacking the myelin sheath. Rebif does not cure MS but it helps reduce the symptoms of MS and decrease the number of relapses.
  • Rebif belongs to the class of medicines known as interferons. It may also be called a disease-modifying drug or an immunosuppressant because it affects how the immune system works.

2. Upsides

  • May be used to treat relapsing forms of MS in adults who are aged over 18. This includes clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease.
  • Helps to inhibit inflammation that can cause MS flare-ups.
  • Decreases the frequency of clinical exacerbations.
  • May also help slow the progression of physical disability associated with MS and reduce the number of relapses.
  • Although the interferon in Rebif is man-made (synthetic), it contains all of the same basic components as the interferon beta-1a that occurs naturally in the human body.
  • Administered by subcutaneous injection under the skin three times a week. It should be administered on the same three days and at the same time, if possible. For example, late afternoon on Monday, Wednesday, and Friday. Doses should be at least 48 hours apart.
  • Self-administration with the Rebif Rebidose autoinjector is straightforward and most people can be taught how to administer it themselves.
  • Available as prefilled syringes and autoinjectors in the following strengths, 8.8mcg, 22mcg, and 44mcg. The colors corresponding to the strengths of the Rebif Rebidose autoinjector are 8.8 mcg (lime green), 22 mcg (yellow), and 44 mcg (teal green).
  • Needs to be store in a refrigerator between 36°F and 46°F (2°C to 8°C). If no refrigerator is available, Rebif may be kept out of a refrigerator at room temperature (36°F to 77°F [2°C to 25°C]) for up to 30 days if kept away from heat and light; however, it should not be put back in a refrigerator after this time. Discard it instead. Do not use if Rebif is expired.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Injection site reactions, flu-like symptoms (such as headache, fatigue, fever, rigors, chest pain, back pain, muscle pain), abdominal pain, and depression are the most common side effects reported. In clinical trials, injection site reactions occurred in 92% of people administered 44mcg group and 89% of those administered 22mcg. Reactions include injection site pain, redness, edema, cellulitis, and necrosis.
  • May decrease peripheral blood counts and leukopenia is common (36% in the 44mcg group and 28% in the 22mcg group). Thrombocytopenia and anemia have also been reported.
  • Not suitable for people who are allergic to natural or recombinant interferon beta, human albumin, or any other ingredient in Rebif. Anaphylaxis is rare with Rebif but may occur even after prolonged use. Be cautious when using Rebif for people with a history of seizure disorders.
  • Use caution in people with depression because Rebif may increase the risk of suicidal thoughts or behaviors. Monitor.
  • May increase the risk of liver disease and asymptomatic elevation of liver enzymes (particularly SGPT) is common with interferon treatment. Use with caution in those with active liver disease, alcohol abuse, increased serum SGPT (more than 2.5 times the upper limit of normal), a history of significant liver disease, or taking other medications that may cause liver toxicity.
  • Cases of thrombotic microangiopathy (TMA), some fatal, have been reported with interferon beta products, including Rebif. Symptoms include fever, microangiopathic hemolytic anemia (schistocytes seen in a blood smear), kidney failure, thrombocytopenia and confusion, drowsiness, or seizures. Monitor and discontinue Rebif if TMA occurs.
  • It is not known if Rebif is safe and effective in children aged < 18 years.
  • Regular blood cell counts and liver function tests are recommended at baseline then every 3 months for the first 6 months then periodically thereafter if stable. More intensive monitoring may be required in people with myelosuppression.
  • Rebif suppresses the immune system
  • There is the potential for immunogenicity with Rebif and the development of antibodies. 24% to 31% of people developed detectable antibodies at least once during treatment.
  • Does not cure MS but it helps reduce the symptoms of MS and decrease the number of relapses.
  • Slow upwards dosage titration is recommended. People should be started at 20% of the prescribed dose three times per week and increased over 4-weeks to either 22mcg three times per week or 44mcg three times per week.
  • Should not be used during pregnancy unless the benefits outweigh the risks. There are no adequate controlled studies in pregnant women. It is not known if Rebif is excreted into breastmilk.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

  • Rebif may be used to reduce the frequency of exacerbations of MS and delay the progression of the disease in adults. It is usually self-administered by SC injection three times per week and the most common side effects are injection site reactions, flu-like symptoms, and a reduction in white blood cell numbers.

5. Tips

  • Make sure the dose of the Rebif Rebidose autoinjector is the correct one prescribed for you. The autoinjector comes in three strengths: 8.8 mcg (lime green), 22 mcg (yellow), and 44 mcg (teal green). Usually, Rebif is started at a smaller dose and then titrated upwards. Always inject the dose that your doctor has prescribed for you. Read the Rebif medication guide before use.
  • Your doctor, nurse, or other health care professional should teach you how to use the autoinjector before you attempt to self-administer it yourself.
  • Inject Rebif Rebidose autoinjector subcutaneously (which means under the skin) into an area of your stomach (but at least 2 inches [5cm] away from your belly button), thigh, buttocks, or the back of your arm. You should rotate sites for each injection (do not use the same site twice in a row) and you should not inject the Rebif Rebidose autoinjector where the skin is bruised, discolored, red, infected, or if there is a rash on the skin.
  • Needs to be administered three times a week. Try to administer it on the same three days and at the same time, if possible. For example, late afternoon on Monday, Wednesday, and Friday. Each Rebif dose should be at least 48 hours apart.
  • Take your Rebif Rebidose autoinjector out of the refrigerator and let it warm up naturally to room temperature for 30 minutes. Do not put it in the microwave or use hot water to heat it. Wash your hands with soap and water. Check the contents of your Rebif Rebidose autoinjector through the transparent housing. The liquid should be clear or slightly yellow. Do not use it if it is cloudy or has particles floating in it. Air bubbles are normal and will not affect your dose. Also, check the expiry date located on the side of the autoinjector and its carton. Do not use it if it has expired.
  • Do not remove the cap of the Rebif Rebidose autoinjector until you are ready to inject it because the autoinjector could roll off the table and become unsterile. Do not use your Rebif Rebidose if it has been dropped more than three feet or looks damaged for any reason.
  • Choose an injection site and wipe it with an alcohol wipe. Let it dry. Pull the Rebif Rebidose cap straight off. Place the Rebif Rebidose on your chosen injection site at a 90° angle (straight up and down). Firmly press until you feel resistance as this unlocks the injector button. As you hold the Rebdiose firmly against your skin, use your thumb to press the injector button. You will hear a click which means the injection has begun.
  • Keep the autoinjector firmly pressed against your skin for at least 10 seconds while the medication is dispensed. Before removing the Rebdose, check that the syringe plunger inside the casing has moved to the bottom and the entire dose has been injected.
  • Lift the autoinjector from the injector site. The safety guard will slide down to protect you from the needle. Do not try to put the needle cap back on the autoinjector. Instead, dispose of it and the autoinjector in an approved sharps bin. If there is blood at the injection site, hold gauze over the site to stop the bleeding and wipe away the blood. Use a small plaster if necessary.
  • Each Rebif Rebidose is administered just one time only. Discard the empty pen in a sharps bin after use and never share your autoinjector with others.
  • Taking acetaminophen or other analgesics on treatment days can help relieve some flu-like symptoms associated with Rebif. But talk with your doctor or pharmacist before taking any other medications with Rebig including those brought over the counter because Rebif can interact with some supplements and some may not be suitable.
  • Tell your doctor if you experience a worsening of your mood because Rebif may increase the risk of depression or suicidal thoughts. Also tell your doctor if you experience any other worrying side effects such as abdominal pain, skin yellowing, an allergic reaction (call 911), seizures, extreme tiredness, easy bruising, and serious reactions around your injection sites, such as blue-black skin, severe pain or severe swelling.
  • Store in a refrigerator between 36°F and 46°F (2°C to 8°C). If no refrigerator is available, they may be kept out of a refrigerator at room temperature (less than 77°F [25°C]) for up to 30 days; however, they should not be put back in a refrigerator after this time. Discard it instead.
  • Tell your doctor if you are pregnant or intend to become pregnant because Rebif may not be suitable for you. Do not breastfeed while being administered Rebif except on your doctor's advice.

6. Response and effectiveness

  • Rebif 22mcg reduced the frequency of MS exacerbations by 29% over 2 years and a 32% reduction was seen with the 44mcg dose. The median time to first exacerbation of MS was 7.6 months in people administered Rebif 22mcg and 9.6 months for people administered Rebif 44mcg compared to 4.5 months for those administered placeboes.
  • A reduction in MRI PD-T2 lesions of 1.2% for the 22mcg group and 3.8% for the 44mcg group was reported after 2 years compared to an increase in PD-T2 lesions of 11% reported in the placebo group.
  • The safety and effectiveness of Rebif beyond 2 years has not been established.
  • 75% of Rebif 44mcg patients were relapse-free at 24 weeks compared to 63% administered Avonex 30mcg. This had reduced to 62% of Rebif 44 mcg patients at 48 weeks and 52% of Avonex 30 mcg patients.

7. Interactions

Medicines that interact with Rebif may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with Rebif. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Rebif interacts with over 250 medications; the majority of these interactions are considered major or moderate. Common medications that may interact with Rebif include:

  • acarbose
  • acetaminophen
  • ACE inhibitors such as benazepril or fosinopril
  • aminophylline
  • antibiotics such as azithromycin, levofloxacin, or nitrofurantoin
  • anticonvulsants, such as phenytoin or valproic acid
  • antidepressants such as nefazodone
  • antifungals such as itraconazole or ketaconazole
  • biologics such as abemaciclib
  • bosentan
  • bupropion
  • cannabidiol
  • cystic fibrosis medicines, such as ivacaftor
  • fingolimod
  • heart medications such as amiodarone or quinapril
  • herbals, such as black cohosh or ginkgo
  • HIV medications such as abacavir, ritonavir, tenofovir, or zidovudine
  • immunosuppressants such as azathioprine, cyclosporine, or natalizumab
  • contrast agents, such as iohexol, iopamidol, or metrizamide
  • isotretinoin
  • leflunomide
  • lomitapide
  • methotrexate
  • naltrexone
  • NSAIDS such as celecoxib, ibuprofen, or diclofenac
  • orlistat
  • other DMARDs such as infliximab
  • other interferons or peginterferons
  • statins, such as atorvastatin, fluvastatin, or simvastatin
  • targeted treatments such as afatinib or gefitinib
  • testosterone
  • tramadol
  • warfarin.

Rebif may have additive immune-suppressing effects when given with any other medications such as anticancer drugs, immune-modulating, or immunosuppressive therapies, which may increase a person's risk for infection.

Note that this list is not all-inclusive and includes only common medications that may interact with Rebif. You should refer to the prescribing information for Rebif for a complete list of interactions.


Further information

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

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

Copyright 1996-2023 Revision date: February 17, 2023.