Advertisement



Drugs A–Z

Interferon Beta-1b

Interferon Beta-1b is a prescription medicine. The sections below reproduce one FDA label for it, named under "Label". Products in other forms, strengths or from other makers have their own labels, which can differ.

Type
Prescription only (Rx)
Brand names
Betaseron
Label
Bayer HealthCare Pharmaceuticals Inc., revised March 3, 2026 · full label on DailyMed
Biosimilars
None approved · details

What it is used for

BETASERON is indicated for the treatment of relapsing forms of multiple sclerosis (MS), to include clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease, in adults. BETASERON is an interferon beta indicated for the treatment of relapsing forms of multiple sclerosis, to include clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease, in adults. ( 1 )

Forms and strengths

For injection: 0.3 mg lyophilized powder in a single-dose vial for reconstitution. For injection: 0.3 mg of lyophilized powder in a single-dose vial for reconstitution ( 3 )

Who should not take it (contraindications)

BETASERON is contraindicated in patients with a history of hypersensitivity to natural or recombinant interferon beta, Albumin (Human), or any other component of the formulation. History of hypersensitivity to natural or recombinant interferon beta, albumin or mannitol ( 4 )

Warnings and precautions

  • Hepatic Injury: Monitor liver function tests and signs and symptoms of hepatic injury; consider discontinuing BETASERON if serious hepatic injury occurs. ( 5.1 , 5.11 )
  • Anaphylaxis and Other Allergic Reactions: Discontinue if anaphylaxis occurs. ( 5.2 )
  • Depression and Suicide: Advise patients to immediately report any symptom of depression and/or suicidal ideation; consider discontinuation of BETASERON if depression occurs. ( 5.3 )
  • Congestive Heart Failure (CHF): Monitor patients with CHF for worsening of cardiac symptoms; consider discontinuation of BETASERON if worsening of CHF occurs. ( 5.4 )
  • Injection Site Reactions Including Necrosis: Do not administer BETASERON into affected area until fully healed; if multiple lesions occur, change injection site or discontinue BETASERON until healing of skin lesions. ( 5.5 )
  • Leukopenia: Monitor complete blood count. ( 5.6 , 5.12 )
  • Thrombotic Microangiopathy: Cases of thrombotic microangiopathy (TMA) have been reported. Discontinue BETASERON if clinical symptoms and laboratory findings consistent with TMA occur and a relationship to BETASERON is suspected. ( 5.7 )
  • Pulmonary Arterial Hypertension: Cases of pulmonary arterial hypertension (PAH) have been reported in patients treated with interferon beta products, including BETASERON. Discontinue BETASERON if PAH is diagnosed. ( 5.8 )
  • Flu-like Symptom Complex: Consider analgesics and/or antipyretics on injection days. ( 5.9 )
  • Drug-induced Lupus Erythematosus: Cases of drug-induced lupus erythematosus have been reported. Discontinue BETASERON if patients develop new characteristic signs and symptoms. ( 5.11 )

5.1 Hepatic Injury Severe hepatic injury including cases of hepatic failure, some of which have been due to autoimmune hepatitis, has been rarely reported in patients taking BETASERON. In some cases, these events have occurred in the presence of other drugs or comorbid medical conditions that have been associated with hepatic injury. Consider the potential risk of BETASERON used in combination with known hepatotoxic drugs or other products (eg, alcohol) prior to BETASERON administration, or when adding new agents to the regimen of patients already on BETASERON. Monitor patients for signs and symptoms of hepatic injury. Consider discontinuing BETASERON if serum transaminase levels significantly increase, or if they are associated with clinical symptoms such as jaundice. Asymptomatic elevation of serum transaminases is common in patients treated with BETASERON. In controlled clinical trials, elevations of SGPT to greater than five times baseline value were reported in 12% of patients receiving BETASERON (compared to 4% on placebo), and increases of SGOT to greater than five times baseline value were reported in 4% of patients receiving BETASERON (compared to 1% on placebo), leading to dose-reduction or discontinuation of treatment in some patients [see Adverse Reactions ( 6.1 )] . Monitor liver function tests [see Warnings and Precautions ( 5.12 )].

5.2 Anaphylaxis and Other Allergic Reactions Anaphylaxis has been reported as a rare complication of BETASERON use. Other allergic reactions have included dyspnea, bronchospasm, tongue edema, skin rash and urticaria [see Adverse Reactions ( 6.1 )] . Discontinue BETASERON if anaphylaxis occurs.

5.3 Depression and Suicide Depression and suicide have been reported to occur with increased frequency in patients receiving interferon beta products, including BETASERON. Advise patients to report any symptom of depression and/or suicidal ideation to their healthcare provider. If a patient develops depression, discontinuation of BETASERON therapy should be considered. In randomized controlled clinical trials, there were three suicides and eight suicide attempts among the 1532 patients on BETASERON compared to one suicide and four suicide attempts among 965 patients on placebo.

5.4 Congestive Heart Failure Monitor patients with pre-existing congestive heart failure (CHF) for worsening of their cardiac condition during initiation of and continued treatment with BETASERON. While beta interferons do not have any known direct-acting cardiac toxicity, cases of CHF, cardiomyopathy, and cardiomyopathy with CHF have been reported in patients without known predisposition to these events, and without other known etiologies being established. In some cases, these events have been temporally related to the administration of BETASERON. Recurrence upon rechallenge was observed in some patients. Consider discontinuation of BETASERON if worsening of CHF occurs with no other etiology.

5.5 Injection Site Reactions Including Necrosis Injection site reactions, including injection site necrosis, can occur with the use of interferon beta products, including BETASERON. Injection site necrosis (ISN) was reported in 4% of BETASERON-treated patients in controlled clinical trials (compared to 0% on placebo) [see Adverse Reactions ( 6.1 )]. Typically, ISN occurs within the first four months of therapy, although postmarketing reports have been received of ISN occurring over one year after initiation of therapy. The necrotic lesions are typically 3 cm or less in diameter, but larger areas have been reported. Generally the necrosis has extended only to subcutaneous fat, but has extended to the fascia overlying muscle. In some lesions where biopsy results are available, vasculitis has been reported. For some lesions, debridement, and/or skin grafting have been required. In most cases healing was associated with scarring. In controlled clinical trials, injection site reactions occurred in 78% of patients receiving BETASERON with injection site necrosis in 4%. Injection site inflammation (42%), injection site pain (16%), injection site hypersensitivity (4%), injection site necrosis (4%), injection site mass (2%), injection site edema (2%), and nonspecific reactions were significantly associated with BETASERON treatment. The incidence of injection site reactions tended to decrease over time. Approximately 69% of patients experienced injection site reactions during the first three months of treatment, compared to approximately 40% at the end of the studies. Injection site abscesses and cellulitis have been reported in the postmarketing setting with use of interferon beta products including BETASERON. Some cases required treatment with hospitalization for surgical drainage and intravenous antibiotics. Periodically evaluate patient understanding and use of aseptic self-injection techniques and procedures, particularly if injection site necrosis has occurred. Patients should be advised of the importance of rotating injection sites with each dose. Whether to discontinue therapy following a single site of necrosis is dependent on the extent of necrosis. For patients who continue therapy with BETASERON after injection site necrosis has occurred, avoid administration of BETASERON into the affected area until it is fully healed. If multiple lesions occur, change injection site or discontinue therapy until healing occurs.

5.6 Leukopenia In controlled clinical trials, leukopenia was reported in 18% of patients receiving BETASERON (compared to 6% on placebo), leading to a reduction of the dose of BETASERON in some patients [see Adverse Reactions ( 6.1 )] . Monitoring of complete blood and differential white blood cell counts is recommended. Patients with myelosuppression may require more intensive monitoring of complete blood cell counts, with differential and platelet counts.

5.7 Thrombotic Microangiopathy Cases of thrombotic microangiopathy (TMA), including thrombotic thrombocytopenic purpura and hemolytic uremic syndrome, some fatal, have been reported with interferon beta products, including BETASERON. Cases have been reported several weeks to years after starting interferon beta products. […]

Side effects (adverse reactions)

The following serious adverse reactions are discussed in more details in other sections of labeling:

  • Hepatic Injury [see Warnings and Precautions ( 5.1 )]
  • Anaphylaxis and Other Allergic Reactions [see Warnings and Precautions ( 5.2 )]
  • Depression and Suicide [see Warnings and Precautions ( 5.3 )]
  • Congestive Heart Failure [see Warnings and Precautions ( 5.4 )]
  • Injection Site Reactions Including Necrosis [see Warnings and Precautions ( 5.5 )]
  • Leukopenia [see Warnings and Precautions ( 5.6 )]
  • Thrombotic Microangiopathy [see Warnings and Precautions ( 5.7 )]
  • Pulmonary Arterial Hypertension [see Warnings and Precautions ( 5.8 )]
  • Flu-like Symptom Complex [see Warnings and Precautions ( 5.9 )]
  • Seizures [see Warnings and Precautions ( 5.10 )]
  • Drug Induced Lupus Erythematosus [see Warnings and Precautions ( 5.11 )] In controlled clinical trials, the most common adverse reactions (at least 5% more frequent on BETASERON than on placebo) were: injection site reaction, lymphopenia, flu-like symptoms, myalgia, leukopenia, neutropenia, increased liver enzymes, headache, hypertonia, pain, rash, insomnia, abdominal pain, and asthenia. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Bayer HealthCare Pharmaceuticals at 1-888-842-2937 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions and over varying lengths of time, adverse reaction rates observed in the clinical trials of BETASERON cannot be directly compared to rates in clinical trials of other drugs, and may not reflect the rates observed in practice. Among 1407 patients with MS treated with BETASERON 0.25 mg every other day (including 1261 patients treated for greater than one year), the most commonly reported adverse reactions (at least 5% more frequent on BETASERON than on placebo) were injection site reaction, lymphopenia, flu-like symptoms, myalgia leukopenia, neutropenia, increased liver enzymes, headache, hypertonia, pain, rash, insomnia, abdominal pain, and asthenia. The most frequently reported adverse reactions resulting in clinical intervention (for example, discontinuation of BETASERON, adjustment in dosage, or the need for concomitant medication to treat an adverse reaction symptom) were depression, flu-like symptom complex, injection site reactions, leukopenia, increased liver enzymes, asthenia, hypertonia, and myasthenia. Table 2 enumerates adverse reactions and laboratory abnormalities that occurred among patients treated with 0.25 mg of BETASERON every other day by subcutaneous injection in the pooled placebo-controlled trials (Study 1-4) at an incidence that was at least 2% more than that observed in the placebo-treated patients [see Clinical Studies ( 14 )] . Table 2: Adverse Reactions and Laboratory Abnormalities in Patients with MS in Pooled Studies 1, 2, 3, and 4 Adverse Reaction Placebo (N=965) BETASERON (N=1407) Blood and lymphatic system disorders Lymphocytes count decreased (<1500/mm3) 66% 86% Absolute neutrophil count decreased (<1500/mm3) 5% 13% White blood cell count decreased (<3000/mm3) 4% 13% Lymphadenopathy 3% 6% Nervous system disorders Headache 43% 50% Insomnia 16% 21% Incoordination 15% 17% Vascular disorders Hypertension 4% 6% Respiratory, thoracic and mediastinal disorders Dyspnea 3% 6% Gastrointestinal disorders Abdominal pain 11% 16% Hepatobiliary disorders Alanine aminotransferase increased (SGPT > 5 times baseline) 4% 12% Aspartate aminotransferase increased (SGOT > 5 times baseline) 1% 4% Skin and subcutaneous tissue disorders Rash 15% 21% Skin disorder 8% 10% Musculoskeletal and connective tissue disorders Hypertonia 33% 40% Myalgia 14% 23% Renal and urinary disorders Urinary urgency 8% 11% Reproductive system and breast disorders Metrorrhagia 7% 9% Impotence 6% 8% General disorders and administration site conditions Injection site reaction "Injection site reaction" comprises all adverse reactions occurring at the injection site (except injection site necrosis), that is, the following terms: injection site reaction, injection site hemorrhage, injection site hypersensitivity, injection site inflammation, injection site mass, injection site pain, injection site edema and injection site atrophy. 26% 78% Asthenia 48% 53% Flu-like symptoms (complex) "Flu-like symptom (complex)" denotes flu syndrome and/or a combination of at least two adverse reactions from fever, chills, myalgia, malaise, sweating. 37% 57% Pain 35% 42% Fever 19% 31% Chills 9% 21% Peripheral edema 10% 12% Chest pain 6% 9% Malaise 3% 6% Injection site necrosis 0% 4% In addition to the Adverse Reactions listed in Table 2 , the following adverse reactions occurred more frequently on BETASERON than on placebo, but with a difference smaller than 2%: alopecia, anxiety, arthralgia, constipation, diarrhea, dizziness, dyspepsia, dysmenorrhea, leg cramps, menorrhagia, myasthenia, nausea, nervousness, palpitations, peripheral vascular disorder, prostatic disorder, tachycardia, urinary frequency, vasodilatation, and weight increase. Laboratory Abnormalities In the four clinical trials (Studies 1, 2, 3, and 4), leukopenia was reported in 18% and 6% of patients in BETASERON- and placebo-treated groups, respectively. No patients were withdrawn or dose reduced for neutropenia in Study 1. Three percent (3%) of patients in Studies 2 and 3 experienced leukopenia and were dose-reduced. Other abnormalities included increase of SGPT to greater than five times baseline value (12%), and increase of SGOT to greater than five times baseline value (4%). In Study 1, two patients were dose reduced for increased hepatic enzymes; one continued on treatment and one was ultimately withdrawn. In Studies 2 and 3, 1.5% of BETASERON patients were dose-reduced or interrupted treatment for increased hepatic enzymes. In Study 4, 1.7% of patients were withdrawn from treatment due to increased hepatic enzymes, two of them after a dose reduction. In Studies 1-4, nine (0.6%) patients were withdrawn from treatment with BETASERON for any laboratory abnormality, including four (0.3%) patients following dose reduction.

6.2 Immunogenicity As with all therapeutic proteins, there is a potential for immunogenicity. Serum samples were monitored for the development of antibodies to BETASERON during Study 1. In patients receiving 0.25 mg every other day 56/124 (45%) were found to have serum neutralizing activity at one or more of the time points tested. In Study 4, neutralizing activity was measured every 6 months and at end of study. At individual visits after start of therapy, activity was observed in 17% up to 25% of the BETASERON-treated patients. Such neutralizing activity was measured at least once in 75 (30%) out of 251 BETASERON patients who provided samples during treatment phase; of these, 17 (23%) converted to negative status later in the study. Based on all the available evidence, the relationship between antibody formation and clinical safety or efficacy is not known. These data reflect the percentage of patients whose test results were considered positive for antibodies to BETASERON using a biological neutralization assay that measures the ability of immune sera to inhibit the production of the interferon-inducible protein, MxA. Neutralization assays are highly dependent on the sensitivity and specificity of the assay. Additionally, the observed incidence of neutralizing activity in an assay may be influenced by several factors including sample handling, timing of sample collection, concomitant medications, and underlying disease. For these reasons, comparison of the incidence of antibodies to BETASERON with the incidence of antibodies to other products may be misleading. Anaphylactic reactions have been reported with the use of BETASERON [see Warnings and Precautions ( 5.2 )].

6.3 Postmarketing Experience The following adverse reactions have been identified during postapproval use of BETASERON. […]

Pregnancy, breastfeeding, children and older adults

Pregnancy: Based on animal data, may cause fetal harm. ( 8.1 )

8.1 Pregnancy Risk Summary Although there have been no well-controlled studies in pregnant women, available data, which includes prospective observational studies, have not generally indicated a drug-associated risk of major birth defects with interferon beta-1b during pregnancy. Administration of BETASERON to monkeys during gestation resulted in increased embryo-fetal death at or above exposures greater than 3 times the human therapeutic dose ( see Animal Data ). In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively. The background risk of major birth defects and miscarriage for the indicated population is unknown. Data Human Data The majority of the observational studies reporting on pregnancies exposed to interferon beta-1b did not identify an association between the use of interferon beta-1b during pregnancy and an increased risk of major birth defects Animal Data When BETASERON (doses ranging from 0.028 to 0.42 mg/kg/day) was administered to pregnant rhesus monkeys throughout the period of organogenesis (gestation days 20 to 70), a dose-related abortifacient effect was observed. The low-effect dose is approximately 3 times the recommended human dose of 0.25 mg on a body surface area (mg/m 2 ) basis. A no-effect dose for embryo-fetal developmental toxicity in rhesus monkeys was not established.

8.2 Lactation Risk Summary There are no data on the presence of BETASERON in human milk, the effects on the breastfed infant, or the effects of the drug on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for BETASERON and any potential adverse effects on the breastfed child from BETASERON or from the underlying maternal condition.

8.4 Pediatric Use Safety and efficacy in pediatric patients have not been established.

8.5 Geriatric Use Clinical studies of BETASERON did not include sufficient numbers of patients aged 65 and over to determine whether they respond differently than younger patients.

How it works

The mechanism of action of BETASERON (interferon beta-1b) in patients with multiple sclerosis is unknown.

Are there biosimilars to Interferon Beta-1b?

No. The FDA has not approved a biosimilar yet.

Biologics have biosimilars rather than generics: highly similar versions with no clinically meaningful differences. Only biosimilars the FDA designates as interchangeable can be swapped at the pharmacy without asking the prescriber, where state law allows; the FDA Purple Book lists which ones are.

Brand-name versions

  • Betaseron Bayer Healthcare Pharms, approved 1993

Source: Drugs@FDA (via openFDA), checked October 29, 2026. Marketing status is what companies report to the FDA; whether a pharmacy stocks a product, and what your insurance covers, can differ.

Dosage:
we do not reproduce dosing instructions. The right dose depends on the person and the condition and is set by the prescriber or pharmacist. Dosage section of the full label.

Interferon beta-1b in the news

We have not covered this medicine yet. Latest news

Recalls

No recalls matched to this medicine in FDA enforcement reports from the last 3 years (or older ones still open). Search all recalls

Get alerts for Interferon Beta-1b

We will email you if the FDA reports a recall, if its shortage status changes, or when we publish news about it — at most one email a day. No account needed.









Source: FDA structured product labeling, retrieved through openFDA. Label text is shown as published by the FDA, without editing; long sections are shortened, marked […]. openFDA data are not validated for clinical use — always check the current label and ask a doctor or pharmacist about your own treatment. Set ID 66311f74-0472-4fa3-848a-06002ca0def5.


Advertisement



Important: this content is for informational purposes only and is not medical advice, a prescribing instruction, or a recommendation to act. Consult a licensed healthcare professional before taking any medication.

Advertisement