interferon beta 1a (Rx)

Brand and Other Names:Avonex, Rebif, more...Rebif Rebidose, AVOSTARTGRIP
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Dosing & Uses

AdultPediatricGeriatric

Dosage Forms & Strengths

prefilled IM syringe (Avonex)

  • 30mcg/0.5mL

prefilled IM autoinjector pen (Avonex)

  • 30mcg/0.5mL

powder for injection (Avonex)

  • 30mcg/vial (30mcg/0.5 mL reconstituted)

prefilled SC syringes titration pack (Rebif)

  • 8.8mcg/0.2mL (6 syringes)
  • 22mcg/0.5mL (6 syringes)

prefilled SC syringe (Rebif)

  • 22mcg/0.5mL
  • 44mcg/0.5mL

prefilled SC autoinjector (Rebif Rebidose)

  • 8.8mcg/syringe
  • 22mcg/syringe
  • 44mcg/syringe

Multiple Sclerosis

Indicated for the treatment of relapsing forms of multiple sclerosis (including clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease) to slow accumulation of physical disability and decrease frequency of clinical exacerbations

Avonex

  • 30 mcg IM qWk
  • May be titrated using the AVOSTARTGRIP titration kit with prefilled IM syringes starting with 7.5 mcg IM for first week, to reduce flu-like symptoms; increase by 7.5 mcg/week for next 3 weeks until recommended dose of 30 mcg/week
  • Administration: Rotate IM injection sites between upper thighs and arms

Rebif 44 mcg target dose

  • Weeks 1-2: 8.8 mcg SC 3 times/wk (at least 48 hr apart)
  • Weeks 3-4: 22 mcg SC 3 times/wk
  • Weeks 5+: 44 mcg SC 3 times/wk
  • Administration: Abdomen (except waistline), thigh, arm, buttocks

Rebif 22 mcg target dose

  • Weeks 1-2: 4.4 mcg SC 3 times/wk (at least 48 hr apart)
  • Weeks 3-4: 11 mcg SC 3 times/wk
  • Weeks 5+: 22 mcg SC 3 times/wk
  • Administration: Abdomen (except waistline), thigh, arm, buttocks

Hepatic Impairment

Rebif: Decrease dose 20-50% if liver function tests increase or leukopenia observed

Dosage Forms & Strengths

prefilled IM syringe (Avonex)

  • 30mcg/0.5 mL

prefilled IM autoinjector pen (Avonex)

  • 30mcg/0.5mL

powder for injection (Avonex)

  • 30mcg/vial (30mcg/0.5 mL reconstituted)

prefilled SC syringes titration pack (Rebif)

  • 8.8mcg/0.2mL (6 syringes)
  • 22mcg/0.5mL (6 syringes)

prefilled SC syringe (Rebif)

  • 22mcg/0.5mL
  • 44mcg/0.5mL

prefilled SC autoinjector (Rebif Rebidose)

  • 8.8mcg/syringe
  • 22mcg/syringe
  • 44mcg/syringe

Multiple Sclerosis (Off-label)

Safety and efficacy not established

Limited data suggests to titrate as in adults

Avonex

  • 30 mcg IM qWk
  • May be titrated using the AVOSTARTGRIP titration kit with prefilled IM syringes starting with 7.5 mcg IM for first week, to reduce flu-like symptoms; increase by 7.5 mcg/week for next 3 weeks until recommended dose of 30 mcg/week
  • Administration: Rotate IM injection sites between upper thighs and arms

Rebif 44 mcg target dose

  • Weeks 1-2: 8.8 mcg SC 3 times/wk (at least 48 hr apart)
  • Weeks 3-4: 22 mcg SC 3 times/wk
  • Weeks 5+: 44 mcg SC 3 times/wk
  • Administration: Abdomen (except waistline), thigh, arm, buttocks

Rebif 22 mcg target dose

  • Weeks 1-2: 4.4 mcg SC 3 times/wk (at least 48 hr apart)
  • Weeks 3-4: 11 mcg SC 3 times/wk
  • Weeks 5+: 22 mcg SC 3 times/wk
  • Administration: Abdomen (except waistline), thigh, arm, buttocks
  • Monitor: Hgb, WBC, Plt, LFTs

Multiple sclerosis

Avonex

30 mcg IM qWk

May be titrated using the AVOSTARTGRIP titration kit with prefilled IM syringes starting with 7.5 mcg IM for first week, to reduce flu-like symptoms; increase by 7.5 mcg/week for next 3 weeks until recommended dose of 30 mcg/week

Administration: Rotate IM injection sites between upper thighs and arms

Monitor: Hgb, WBC, Plt, LFTs

Rebif 44 mcg target dose

Weeks 1-2: 8.8 mcg SC 3 times/wk (at least 48 hr apart)

Weeks 3-4: 22 mcg SC 3 times/wkWeeks 5+: 44 mcg SC 3 times/wk

Administration: Abdomen (except waistline), thigh, arm, buttocks

Monitor: Hgb, WBC, Plt, LFTs

Rebif 22 mcg target dose

Weeks 1-2: 4.4 mcg SC 3 times/wk (at least 48 hr apart)

Weeks 3-4: 11 mcg SC 3 times/wk

Weeks 5+: 22 mcg SC 3 times/wk

Administration: Abdomen (except waistline), thigh, arm, buttocks

Monitor: Hgb, WBC, Plt, LFTs

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Interactions

Interaction Checker

and interferon beta 1a

No Results

     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

            All Interactions Sort By:
             activity indicator 

            Contraindicated (0)

              Serious - Use Alternative (3)

              • deferiprone

                deferiprone, interferon beta 1a. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid use of deferiprone with other drugs known to be associated with neutropenia or agranulocytosis; if an alternative is not possible, monitor absolute neutrophil count more frequently.

              • pexidartinib

                interferon beta 1a and pexidartinib both increase Other (see comment). Avoid or Use Alternate Drug. Pexidartinib can cause hepatotoxicity. Avoid coadministration of pexidartinib with other products know to cause hepatoxicity.

              • pretomanid

                interferon beta 1a, pretomanid. Either increases toxicity of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Pretomanid regimen associated with hepatotoxicity. Avoid alcohol and hepatotoxic agents, including herbal supplements and drugs other than bedaquiline and linezolid.

              Monitor Closely (10)

              • acalabrutinib

                acalabrutinib, interferon beta 1a. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may increase risk of myelosuppressive effects.

              • ansofaxine

                ansofaxine, interferon beta 1a. Either increases effects of the other by immunosuppressive effects; risk of infection. Use Caution/Monitor. Consider the risk of additive immune system effects when coadministering immunosuppressive therapies with coadministration. When switching from therapies with immune effects, take into account the duration and mechanism of action of these therapies when initiating ofatumumab SC.

              • hydroxyurea

                interferon beta 1a, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Cutaneous vasculitic toxicities (eg, vasculitic ulcerations and gangrene) were reported during therapy with hydroxyurea in patients with a history of, or currently receiving, interferon therapy.

              • ifosfamide

                ifosfamide, interferon beta 1a. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Ifosfamide may enhance the toxicities of myelosuppressive agents. Monitor for increased risk of myelosuppression.

              • isavuconazonium sulfate

                interferon beta 1a and isavuconazonium sulfate both decrease immunosuppressive effects; risk of infection. Use Caution/Monitor.

              • lomustine

                lomustine, interferon beta 1a. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may increase risk of myelosuppressive effects.

              • ozanimod

                ozanimod, interferon beta 1a. Either increases effects of the other by immunosuppressive effects; risk of infection. Use Caution/Monitor. Coadministration with immunosuppressive therapies may increase the risk of additive immune effects during therapy and in the weeks following administration. When switching from drugs with prolonged immune effects, consider the half-life and mode of action of these drugs in order to avoid unintended additive immunosuppressive effects.

              • siponimod

                siponimod and interferon beta 1a both increase immunosuppressive effects; risk of infection. Use Caution/Monitor. Caution if coadministered because of additive immune effects during such therapy and in the weeks following administration. Siponimod can generally be started immediately after discontinuation of beta interferon.

              • tobramycin inhaled

                tobramycin inhaled and interferon beta 1a both increase nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Avoid concurrent or sequential use to decrease risk for ototoxicity

              • zidovudine

                interferon beta 1a increases levels of zidovudine by decreasing renal clearance. Use Caution/Monitor. Interferons may enhance potential for adverse effects. Patients should be monitored for signs and symptoms of increased myelosuppression and liver decompensation.

              Minor (1)

              • natalizumab

                interferon beta 1a increases levels of natalizumab by decreasing renal clearance. Minor/Significance Unknown.

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              Adverse Effects

              >10%

              Injection site reactions (83% [Rebif]; 28% [Avonex])

              Headache (67%)

              Flu-like syndrome (61%)

              Muscle ache (34%)

              Nausea (33%)

              URT infection (14%)

              Pain (24%)

              Fever (23%)

              Asthenia (21%)

              Diarrhea (16%)

              Dizziness (15%)

              Infection (11%)

              Dyspepsia (11%)

              1-10%

              Abdominal pain (9%)

              Anemia (8%)

              Chest pain (6%)

              <1%

              Aggravation of seizure disorders

              Postmarketing Reports

              Autoimmune disorders: Drug-induced lupus erythematosus, autoimmune hepatitis

              Blood and lymphatic system disorders: Thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS), hemolytic anemia

              Eye disorders: Retinal vascular disorders (ie, retinopathy, cotton wool spots or obstruction of retinal artery or vein)

              Skin and subcutaneous tissue disorders: Erythema multiforme, Stevens-Johnson syndrome

              Hyperhidrosis

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              Warnings

              Contraindications

              Hypersensitivity to beta interferons, albumin (for albumin-containing formulations)

              Cautions

              Hepatic impairment, pregnancy, lactation, depression (may cause worsening, suicidal ideation)

              Risk of rare but potentially severe hepatic damage

              Fllu-like symptoms may occur

              Caution in patients with existing cardiovascular disease (angina, heart failure, etc)

              Autoimmune disorders (autoimmune hepatitis; idiopathic thrombocytopenia) reported

              Efficacy in primary progressive MS not demonstrated conclusively; not recommended

              Cases of thrombotic microangiopathy, including thrombotic thrombocytopenic purpura and hemolytic uremic syndrome, some fatal, reported; some cases have been reported several weeks to years after starting interferon beta products; discontinue therapy if clinical symptoms and laboratory findings consistent with TMA occur, and manage as clinically indicated

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              Pregnancy & Lactation

              Pregnancy

              Data from a large population-based cohort study, as well as other published studies over several decades, have not identified a drug-associated risk of major birth defects with use during early pregnancy

              Findings regarding a potential risk for low birth weight or miscarriage with use of interferon beta products in pregnancy have been inconsistent

              Animal data

              • In a study in pregnant monkeys, administration of interferon beta during pregnancy resulted in an increased rate of abortion at doses greater than those used clinically

              Lactation

              Limited published literature has described the presence of interferon beta-1a products in human milk at low levels; there are no data on effects of interferon beta-1a on milk production

              Therefore, developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for therapy and any potential adverse effects on breastfed infant from drug or from underlying maternal condition

              Pregnancy Categories

              A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

              B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

              C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

              D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

              X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

              NA: Information not available.

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              Pharmacology

              Mechanism of Action

              Recombinant interferon; antiviral, antiproliferative, immunoregulatory protein; alters response to surface antigen and may enhance immune cell activities

              Pharmacokinetics

              Onset of action: 12 hr (Avonex)

              Duration: 4 days (Avonex)

              Peak plasma time: 7.8-9.8 hr (IM); 16 hr (SC)

              Concentration: 5.1±1.7 IU/mL (SC)

              AUC: 294±81 IU.hr/mL (SC)

              Half-Life: 8.6-10 hr (IM); 69±37 hr (SC)

              Clearance: 33-55 L/hr (SC)

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              Images

              BRAND FORM. UNIT PRICE PILL IMAGE
              Avonex intramuscular
              -
              30 mcg/0.5 mL device
              Avonex intramuscular
              -
              30 mcg/0.5 mL syringe

              Copyright © 2010 First DataBank, Inc.

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              Patient Handout

              Patient Education
              interferon beta-1a intramuscular

              INTERFERON BETA-1A PREFILLED SYRINGE - INJECTION

              (IN-ter-FEER-on BAY-ta-wun-ay)

              COMMON BRAND NAME(S): Avonex

              USES: This medication is used to treat multiple sclerosis (MS). Interferon is not a cure for MS, but it may help to slow disease worsening and decrease flare-ups of symptoms (such as balance problems, numbness, or weakness).

              HOW TO USE: Read the Medication Guide and Instructions for Use provided by your pharmacist before you start using interferon beta-1A and each time you get a refill. If you have any questions, ask your doctor or pharmacist.If you are using this medication at home, learn all preparation and usage instructions from your health care professional. Before using, check this product visually for particles or discoloration. If either is present, do not use the liquid. Learn how to store and discard medical supplies safely.To increase comfort, remove this medication from the refrigerator and let it warm to room temperature for about 30 minutes before injecting. Do not warm up this medication in any other way such as heating in the microwave or placing in hot water.Inject this medication into a muscle as directed by your doctor, usually once a week. It is best to use this medication near bedtime to reduce side effects.Before injecting each dose, clean the injection site with rubbing alcohol. Change the injection site each time to lessen injury. Do not inject into skin that is red, sore, scarred, or infected. If you are using the prefilled syringe, inject this medication into the thigh or upper arm as directed by your doctor. If you are using the autoinjector, inject into the upper outer thigh as directed. Tell your doctor of any skin reactions that do not go away after a few days.The dosage is based on your medical condition and response to treatment. To reduce your risk of side effects, your doctor may direct you to start this medication at a low dose and gradually increase your dose. Follow your doctor's instructions carefully. Use this medication regularly to get the most benefit from it. To help you remember, use it on the same day each week.Tell your doctor if your condition gets worse.

              SIDE EFFECTS: Pain, swelling, or redness at the injection site may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.Most people have flu-like symptoms such as headache, tiredness, fever, chills, and muscle aches when they first start this medication. These symptoms usually last about 1 day after the injection and improve or go away after a few months of continued use. You can lessen these side effects by injecting this medicine at bedtime and by using fever reducers/pain relievers such as acetaminophen or ibuprofen before each dose. Ask your doctor or pharmacist for more information.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor right away if you have any serious side effects, including: mental/mood changes (such as new or worsening depression, thoughts of suicide, psychosis), feeling too hot or cold (more than others around you), blue fingers/toes, easy bleeding/bruising, pus or change in skin color at the injection site, joint pain/swelling, signs of kidney problems (such as a change in the amount of urine), signs of liver problems (such as nausea/vomiting that doesn't stop, loss of appetite, stomach/abdominal pain, yellowing eyes/skin, dark urine), new or worsening symptoms of heart failure (such as shortness of breath, swelling ankles/feet, unusual tiredness, unusual/sudden weight gain).Get medical help right away if you have any very serious side effects, including: seizures.This medication may lower your ability to fight infections. This may make you more likely to get a serious (rarely fatal) infection or make any infection you have worse. Tell your doctor right away if you have any signs of infections (such as sore throat that doesn't go away, fever, chills, cough).A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

              PRECAUTIONS: Before using interferon, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients (such as natural rubber/latex), which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: bleeding/blood problems, heart problems (such as heart failure, angina, fast/irregular heartbeat), liver disease, mental/mood disorders (such as depression, psychosis, suicidal thoughts), seizure disorder, thyroid disease.Interferon can make you more likely to get infections or may worsen any current infections. Avoid contact with people who have infections that may spread to others (such as chickenpox, measles, flu). Consult your doctor if you have been exposed to an infection or for more details.Do not have immunizations/vaccinations without the consent of your doctor. Avoid contact with people who have recently received live vaccines (such as flu vaccine inhaled through the nose).Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.This medication passes into breast milk in small amounts, but is unlikely to harm a nursing infant. Consult your doctor before breast-feeding.

              DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

              OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.

              NOTES: Do not share this medication with others.Lab and/or medical tests (such as complete blood count, liver/thyroid function) should be done while you are using this medication. Keep all medical and lab appointments.

              MISSED DOSE: If you miss a dose, use it as soon as you remember. Do not use this medication 2 days in a row. Do not double the dose to catch up. Follow your usual schedule the next week.

              STORAGE: Store in the refrigerator away from light. Do not freeze. This medication may also be stored at room temperature for up to 7 days. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

              Information last revised August 2021. Copyright(c) 2021 First Databank, Inc.

              IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

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              Formulary

              FormularyPatient Discounts

              Adding plans allows you to compare formulary status to other drugs in the same class.

              To view formulary information first create a list of plans. Your list will be saved and can be edited at any time.

              Adding plans allows you to:

              • View the formulary and any restrictions for each plan.
              • Manage and view all your plans together – even plans in different states.
              • Compare formulary status to other drugs in the same class.
              • Access your plan list on any device – mobile or desktop.

              The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

              Tier Description
              1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
              2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
              3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
              4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
              5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
              6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
              NC NOT COVERED – Drugs that are not covered by the plan.
              Code Definition
              PA Prior Authorization
              Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
              QL Quantity Limits
              Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
              ST Step Therapy
              Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
              OR Other Restrictions
              Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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              Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.