Note: This document contains side effect information about interferon alfa-2b. Some of the dosage forms listed on this page may not apply to the brand name Intron A.
Common side effects of Intron A include: hemolytic anemia, abdominal pain, cough, depression, dyspnea, fever, flu-like symptoms, nausea, thrombocytopenia, and vomiting. See below for a comprehensive list of adverse effects.
Applies to interferon alfa-2b: injection powder for solution, injection solution
Injection route (Solution; Powder for Solution)
Alpha interferons, including interferon alfa-2b, cause or aggravate fatal or life-threatening neuropsychiatric, autoimmune, ischemic, and infectious disorders. Patients should be monitored closely with periodic clinical and laboratory evaluations. Patients with persistently severe or worsening signs or symptoms of these conditions should be withdrawn from therapy. In many but not all cases these disorders resolve after stopping interferon alfa-2b therapy.
Along with its needed effects, interferon alfa-2b (the active ingredient contained in Intron A) 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 while taking interferon alfa-2b:
Some side effects of interferon alfa-2b 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:
Applies to interferon alfa-2b: injectable kit, injectable powder for injection, injectable solution
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.
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)
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
Aplastic anemia and pure red cell aplasia have also been reported during postmarketing experience.
Myositis has also been reported during postmarketing experience.
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
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
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)
Pancreatitis has also been reported during postmarketing experience.
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.
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
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 (the active ingredient contained in Intron A) (3 x 10 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.
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
Psychosis (including hallucinations) has also been reported during postmarketing experience.
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
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.
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
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.
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
Injection site necrosis has also been reported during postmarketing experience.
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
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.
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
Serous retinal detachment has also been reported during postmarketing experience.
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
Cardiovascular side effects (especially arrhythmia) appeared to be associated with preexisting cardiovascular disease and prior use of cardiotoxic agents.
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
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
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
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.
Frequency not reported: Allergic reaction
Postmarketing reports: Acute hypersensitivity reactions (including anaphylaxis, angioedema, urticaria, bronchoconstriction)
Medically reviewed by BestRx Medical Team Last updated on 1/1/2020.
Source: Drugs.com Intron A