Interferon Alfa-2b Side Effects

Medically reviewed by Drugs.com. Last updated on Oct 10, 2024.

Applies to interferon alfa-2b: injection solution.

Other dosage forms:

• injection solution reconstituted

Important warnings This medicine can cause some serious health issues

• Alpha interferons may cause mental health problems or make them worse.

  Suicide or suicidal thoughts, thoughts of hurting others, depression, forceful actions, hallucinations, and other mood or behavior problems have happened during treatment and within 6 months after the last dose.

  Relapse of drug addiction has also happened.

  Alpha interferons may also cause or make infections, blood flow problems, or autoimmune diseases worse.

  Sometimes, these may be deadly.

  If you think you have any of these health problems, call your doctor right away. Side effects such as high or low blood pressure, a fast or abnormal heartbeat, chest pain or pressure, trouble breathing, heart attacks, and strokes have happened.

  Closely read the part in this leaflet which lists when to call your doctor.

  Many times, but not every time, these side effects get better after stopping this drug.

Serious side effects of interferon alfa-2b

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
• Signs of infection like fever, chills, very bad sore throat, ear or sinus pain, cough, more sputum or change in color of sputum, pain with passing urine, mouth sores, or wound that will not heal.
• Signs of a pancreas problem (pancreatitis) like very bad stomach pain, very bad back pain, or very bad upset stomach or throwing up.
• Signs of thyroid problems like change in weight; feeling nervous, excitable, restless, or weak; hair thinning; depression; neck swelling; not able to focus; trouble with heat or cold; menstrual changes; shakiness; or sweating.
• Mental, mood, or behavior changes that are new or worse.
• Any unexplained bruising or bleeding.
• Black, tarry, or bloody stools.
• Throwing up blood or throw up that looks like coffee grounds.
• Weakness on 1 side of the body, trouble speaking or thinking, change in balance, drooping on one side of the face, or blurred eyesight.
• Shortness of breath, a big weight gain, or swelling in the arms or legs.
• Very bad headache.
• Very bad belly pain.
• A burning, numbness, or tingling feeling that is not normal.
• Memory problems or loss.
• Feeling confused.
• Trouble walking.
• Not able to pass urine or change in how much urine is passed.
• A change in weight without trying.
• Anxiety.
• Change in look of teeth or gums.

Other side effects of interferon alfa-2b

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Feeling dizzy, sleepy, tired, or weak.
• Upset stomach or throwing up.
• Irritation where the shot is given.
• Dry mouth.
• Diarrhea or constipation.
• Not hungry.
• Hair thinning.
• Trouble sleeping.
• Change in taste.
• Weight loss.
• Flu-like signs. These include headache, weakness, fever, shakes, aches, pains, and sweating. Mild pain drugs may help.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.

For healthcare professionals

Applies to interferon alfa-2b: injectable kit, injectable powder for injection, injectable solution.

General adverse events

Clinical trials were conducted for various indications using a wide range of doses (from 6 million international units/m2/week in hairy cell leukemia up to 100 million international units/m2/week in melanoma). Most side effects reported during clinical trials were mild to moderate in severity and manageable. Some side effects were transient and most diminished with continued therapy. Influenza-like symptoms (mainly fever, headache, rigors/chills, myalgia, malaise, and fatigue) were reported most often; these side effects were reversible within 72 hours after interrupting or stopping therapy. Side effects were dose-related. In general, more severe toxicities were observed at higher doses; hematologic, hepatic, cardiovascular, and neurologic toxicities were more common with higher doses.

The manufacturer product information for ribavirin should be consulted, if applicable.^[Ref]

Other

• Very common (10% or more): Fatigue (up to 96%), pyrexia (up to 94%), influenza-like symptoms (up to 79%), asthenia (up to 63%), chills (up to 54%), rigors (up to 42%), chest pain (up to 28%), irritability (up to 22%), unspecified pain (up to 18%), moniliasis (up to 17%), malaise (up to 14%), decreased weight (up to 13%), viral infection
• Common (1% to 10%): Facial edema, nonspecific infection, peripheral edema, herpes simplex resistance, thirst, flushing, breast pain
• Uncommon (0.1% to 1%): Bacterial infection
• Rare (0.01% to 0.1%): Sepsis, resistance mechanism disorders (e.g., altered resistance to infection [rarely life-threatening or fatal]), weakness
• Very rare (less than 0.01%): Cachexia, earache, hot flashes/flushes, fungal infection, malignant hyperpyrexia
• Frequency not reported: Hernia, edema, hypothermia, nonspecific inflammation, mastitis, increased weight, substernal chest pain, hyperthermia, abscess, Haemophilus, infection, parasitic infection, otitis media, Trichomonas
• Postmarketing reports: Asthenic conditions (including asthenia, malaise, fatigue)^[Ref]

Hematologic

• Very common (10% or more): Decreased granulocyte count (up to 92%), neutropenia (up to 92%), decreased WBC count (up to 68%), decreased hemoglobin (up to 32%), anemia (up to 27%), decreased platelet count (up to 15%), leukopenia
• Common (1% to 10%): Thrombocytopenia, bleeding, lymphadenopathy, lymphopenia
• Very rare (less than 0.01%): Aplastic anemia, pure red cell aplasia, hemolytic anemia, coagulation disorder, splenomegaly
• Frequency not reported: Hypochromic anemia, granulocytopenia, lymphadenitis, lymphocytosis, thrombocytopenia purpura
• Postmarketing reports: Pancytopenia (concurrent anemia, leukopenia, thrombocytopenia), idiopathic thrombocytopenia purpura, thrombotic thrombocytopenic purpura^[Ref]

Aplastic anemia and pure red cell aplasia have also been reported during postmarketing experience.^[Ref]

Musculoskeletal

• Very common (10% or more): Myalgia (up to 75%), musculoskeletal pain (up to 21%), arthralgia (up to 19%), back pain (up to 19%)
• Common (1% to 10%): Arthritis
• Rare (0.01% to 0.1%): Rhabdomyolysis (sometimes serious), myositis, leg cramps
• Very rare (less than 0.01%): Arthrosis, bone pain, muscle weakness, myopathy
• Frequency not reported: Arthritis aggravated, bone disorder, carpal tunnel syndrome, muscle atrophy, tendinitis, rheumatoid arthritis (new or aggravated), spondylitis, twitching^[Ref]

Myositis has also been reported during postmarketing experience.^[Ref]

Metabolic

• Very common (10% or more): Anorexia (up to 69%), increased alkaline phosphatase (up to 13%)
• Common (1% to 10%): Hypocalcemia, dehydration, hyperuricemia
• Uncommon (0.1% to 1%): Increased LDH
• Rare (0.01% to 0.1%): Diabetes mellitus, hyperglycemia, increased appetite
• Very rare (less than 0.01%): Acidosis, aggravation of diabetes mellitus, hypercalcemia, hypertriglyceridemia
• Frequency not reported: Alcohol intolerance^[Ref]

Gastrointestinal

• Very common (10% or more): Nausea (up to 66%), diarrhea (up to 45%), vomiting (up to 32%), dry mouth (up to 28%), abdominal pain (up to 23%), right upper quadrant pain (up to 15%), constipation (up to 14%), gingivitis (up to 14%), stomatitis, dyspepsia
• Common (1% to 10%): Loose stools, gastrointestinal (GI) disorder, ulcerative stomatitis, glossitis
• Rare (0.01% to 0.1%): Gingival bleeding
• Very rare (less than 0.01%): Abdominal distension, colitis, dysphagia, eructation, esophagitis, flatulence, gastric ulcer, GI hemorrhage, GI mucosal discoloration, gum hyperplasia, ileus, increased saliva, ischemic colitis, melena, oral leukoplakia, pancreatitis, rectal bleeding after stool, rectal hemorrhage, tenesmus, tongue disorder, ulcerative colitis
• Frequency not reported: Abdominal ascites, gallstones, gastritis, gastroenteritis, halitosis, hemorrhoids, intestinal disorder, mouth ulceration, mucositis, oral hemorrhage, tooth disorder, periodontal disorder (not otherwise specified), dental disorder (not otherwise specified)^[Ref]

Pancreatitis has also been reported during postmarketing experience.^[Ref]

Hepatic

• Very common (10% or more): Elevated AST (up to 63%), elevated ALT (up to 15%)
• Common (1% to 10%): Hepatomegaly
• Rare (0.01% to 0.1%): Hepatotoxicity (including fatality)
• Very rare (less than 0.01%): Abnormal hepatic function tests, bilirubinemia, hepatic encephalopathy, hepatic failure, hepatosplenomegaly, jaundice
• Frequency not reported: Biliary pain, hepatitis, increased transaminases (AST/ALT), worsening liver disease^[Ref]

Worsening liver disease, including jaundice, hepatic encephalopathy, hepatic failure, and death have been reported after use of this drug in patients with decompensated liver disease, autoimmune hepatitis, or history of autoimmune disease, and in immunosuppressed transplant recipients.^[Ref]

Nervous system

• Very common (10% or more): Headache (up to 62%), somnolence (up to 33%), dizziness (up to 24%), altered taste/taste perversion (up to 24%), paresthesia (up to 21%), impaired concentration (up to 14%), amnesia (up to 14%)
• Common (1% to 10%): Hypoesthesia, vertigo, tremor, migraine, tinnitus
• Uncommon (0.1% to 1%): Peripheral neuropathy
• Rare (0.01% to 0.1%): Impaired consciousness, neuropathy, polyneuropathy, seizure
• Very rare (less than 0.01%): Abnormal coordination, abnormal gait, aphasia, ataxia, central nervous system dysfunction, cerebrovascular hemorrhage, cerebrovascular ischemia, coma, convulsions, deafness, dementia, dystonia, encephalopathy, extrapyramidal disorder, hearing disorder, hearing loss, hyperacusis, hyperesthesia, hyperkinesia, hypertonia, oculomotor nerve paralysis, paralysis, paresis, speech disorder, stupor, syncope, taste loss
• Frequency not reported: Bell's palsy, hearing impairment, hypokinesia, hyporeflexia, labyrinthine disorder, loss of consciousness, mononeuropathies, neuralgia, neuritis, parosmia, stroke, frontal subcortical dementia, choreic movements mimicking Huntington's disease^[Ref]

Impaired consciousness included cases of encephalopathy.

Frontal subcortical dysfunction and choreic movements of the limbs appeared in a 68-year-old woman almost 2 years after the start of interferon alfa-2b (3 x 10[6] units/day) for chronic myeloid leukemia. She had no history of psychiatric disorders and no hereditary neurodegenerative disease with long-term recombinant interferon therapy. Symptoms of personality changes, short memory loss, and choreic movements progressively worsened over a 4 month period until she became bedridden. One month after this drug was discontinued, patient's cognitive performance had improved and choreic movements had disappeared. Clinical examination of her cognitive performances at six and 12 months later were normal.

Peripheral neuropathy and hearing loss have also been reported during postmarketing experience.^[Ref]

Psychiatric

• Very common (10% or more): Depression (up to 40%), confusion (up to 12%), insomnia (up to 12%), anxiety, emotional lability, nervousness, agitation
• Common (1% to 10%): Decreased libido, sleep disorder
• Uncommon (0.1% to 1%): Suicidal ideation, suicide attempt, suicide
• Rare (0.01% to 0.1%): Aggressive behavior (sometimes directed against others), psychosis (including hallucinations)
• Very rare (less than 0.01%): Abnormal thinking, apathy, depression aggravated, feeling of ebriety, neurosis, paroniria, personality disorder
• Frequency not reported: Abnormal dreaming, delirium, manic depression, mania, psychosis, mental status change, bipolar disorders
• Postmarketing reports: Homicidal ideation^[Ref]

Psychosis (including hallucinations) has also been reported during postmarketing experience.^[Ref]

Dermatologic

• Very common (10% or more): Alopecia (up to 38%), rash (up to 25%), increased sweating (up to 21%), pruritus (up to 11%), dry skin
• Common (1% to 10%): Dermatitis, purpura, herpes simplex, psoriasis (new or aggravated), maculopapular rash, erythematous rash, eczema, erythema, skin disorder
• Very rare (less than 0.01%): Abnormal hair texture, acne, chloasma, dermatitis lichenoides, epidermal necrolysis, erythema multiforme, furunculosis, increased hair growth, melanosis, nail disorders, nonherpetic cold sores, photosensitivity, skin depigmentation, skin discoloration, Stevens-Johnson syndrome, toxic epidermal necrolysis, urticaria, vitiligo
• Frequency not reported: Cellulitis, cold and clammy skin, erythema nodosum, folliculitis, herpes zoster, lipoma, pallor, sebaceous cyst, skin nodule, urticaria, hair discoloration, trichomegaly, radiation recall dermatitis (manifested as erythematous macular rash in region of irradiation), aseptic necrosis of the skin and ulceration, lipoatrophy, cutaneous vasculitides^[Ref]

Case reports of aseptic necrosis of the skin and ulceration have been described in patients with Kaposi's sarcoma associated with HIV infection treated with this drug.

Erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis, and urticaria have also been reported during postmarketing experience.^[Ref]

Respiratory

• Very common (10% or more): Dyspnea (up to 34%), coughing (up to 31%), pharyngitis (up to 31%), sinusitis (up to 21%), nonproductive cough (up to 14%)
• Common (1% to 10%): Nasal congestion, bronchitis, rhinitis, epistaxis, respiratory disorder, rhinorrhea
• Rare (0.01% to 0.1%): Pneumonia, pulmonary infiltrates, pneumonitis
• Very rare (less than 0.01%): Bronchospasm, hypoxia, laryngitis, pleural pain, pulmonary edema, pulmonary embolism, pulmonary fibrosis, sneezing, stridor, wheezing
• Frequency not reported: Asthma, dysphonia, hemoptysis, hypoventilation, pleural effusion, orthopnea, pneumothorax, pulmonary arterial hypertension, rales, respiratory insufficiency, tonsillitis, tracheitis, upper respiratory tract infection, severe asthma
• Postmarketing reports: Pulmonary hypertension^[Ref]

Pulmonary arterial hypertension (PAH) has been reported with alpha interferons, particularly in patients with risk factors for PAH (e.g., portal hypertension, HIV infection, cirrhosis). Such events occurred at various time points normally several months after starting interferon alfa therapy.

Severe asthma developed in 2 patients as soon as 8 weeks after the start of this drug in patients diagnosed with chronic hepatitis C and mild asthma.

Pulmonary fibrosis has also been reported during postmarketing experience.^[Ref]

Local

• Very common (10% or more): Injection site inflammation (up to 20%), injection site reaction
• Common (1% to 10%): Injection site pain
• Rare (0.01% to 0.1%): Injection site disorders
• Very rare (less than 0.01%): Injection site necrosis
• Frequency not reported: Burning, injection site bleeding, itching^[Ref]

Injection site necrosis has also been reported during postmarketing experience.^[Ref]

Renal

• Very common (10% or more): Increased serum urea nitrogen levels (up to 12%)
• Common (1% to 10%): Increased serum creatinine
• Rare (0.01% to 0.1%): Renal failure, renal insufficiency
• Very rare (less than 0.01%): Nephrotic syndrome, nephrosis

Nephrotic syndrome, renal failure, and renal insufficiency have also been reported during postmarketing experience.

Genitourinary

• Very common (10% or more): Amenorrhea (up to 12%)
• Common (1% to 10%): Polyuria, urinary tract infection, micturition frequency, dysmenorrhea, menorrhagia, menstrual disorder, vaginal disorder
• Very rare (less than 0.01%): Cystitis, hematuria, impotence, leukorrhea, micturition disorder, nocturia, oliguria, urinary incontinence, uterine bleeding, vaginal hemorrhage
• Frequency not reported: Albumin/protein in urine, dysuria, genital pruritus, incontinence, menstrual irregularity, pelvic pain, penis disorder, scrotal/penile edema, sexual dysfunction, vaginal dryness^[Ref]

Ocular

• Very common (10% or more): Blurred vision
• Common (1% to 10%): Conjunctivitis, abnormal vision, eye pain, lacrimal gland disorder
• Rare (0.01% to 0.1%): Retinal hemorrhage, retinopathies (including macular edema), retinal artery or vein obstruction, optic neuritis, papilledema, loss of visual acuity or visual field, cotton wool spots
• Very rare (less than 0.01%): Diplopia, dry eyes, night blindness, periorbital edema, photophobia, retinal disorder, serous retinal detachment, stye
• Frequency not reported: Lacrimation, nystagmus
• Postmarketing reports: Vogt-Koyanagi-Harada syndrome^[Ref]

Serous retinal detachment has also been reported during postmarketing experience.^[Ref]

Cardiovascular

• Common (1% to 10%): Hypertension, palpitations, tachycardia
• Uncommon (0.1% to 1%): Hypotension
• Rare (0.01% to 0.1%): Cardiomyopathy, peripheral ischemia
• Very rare (less than 0.01%): Angina pectoris, arrhythmia, atrial fibrillation, bradycardia, cardiac failure, cardiac ischemia, cyanosis, extrasystoles, myocardial infarction, postural hypotension, thrombophlebitis
• Frequency not reported: Arteritis, cardiomegaly, coronary artery disorder, cyanosis of the hand, heart valve disorder, hematoma, phlebitis, poor peripheral circulation, polyarteritis nodosa, Raynaud's disease, superficial phlebitis, thrombosis, varicose vein, vasculitis, congestive heart failure, pericardial effusion^[Ref]

Cardiovascular side effects (especially arrhythmia) appeared to be associated with preexisting cardiovascular disease and prior use of cardiotoxic agents.^[Ref]

Endocrine

• Common (1% to 10%): Hypothyroidism, hyperthyroidism
• Very rare (less than 0.01%): Gynecomastia, virilism
• Frequency not reported: Goiter, increased thyroid-stimulating hormone levels
• Postmarketing reports: Hypopituitarism^[Ref]

Immunologic

• Very rare (less than 0.01%): Sarcoidosis, exacerbation of sarcoidosis, increased gamma globulins, transplant rejection
• Frequency not reported: Autoimmune disorders, immune-mediated disorders
• Postmarketing reports: Systemic lupus erythematosus^[Ref]

A broad range of autoimmune and immune-mediated disorders have been reported with alpha interferons including thyroid disorders, systemic lupus erythematosus, rheumatoid arthritis (new or aggravated), idiopathic and thrombotic thrombocytopenic purpura, vasculitis, neuropathies (including mononeuropathies), and Vogt-Koyanagi-Harada syndrome.

Sarcoidosis and exacerbation of sarcoidosis have also been reported during postmarketing experience.^[Ref]

Hypersensitivity

• Frequency not reported: Allergic reaction
• Postmarketing reports: Acute hypersensitivity reactions (including anaphylaxis, angioedema, urticaria, bronchoconstriction)

Further information

Interferon alfa-2b side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

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