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Interferon Alfa-2b

Pronunciation: IN-ter-FEER-on AL-fa
Class: Immunomodulator

Trade Names

Intron A
- Injection, lyophilized powder for solution (with 1 mL diluent) 10 million units/vial
- Injection, lyophilized powder for solution (with 1 mL diluent) 18 million units/vial
- Injection, lyophilized powder for solution (with 1 mL diluent) 50 million units/vial
- Multiple-dose pen (solution for injection) 18 million units/6 doses (contains 22.5 million units per 1.5 mL pen)
- Multiple-dose pen (solution for injection) 30 million units/6 doses (contains 37.5 million units per 1.5 mL pen)
- Multiple-dose pen (solution for injection) 60 million units/6 doses (contains 75 million units per 1.5 mL pen)
- Solution for injection 18 million units (6 mg/mL multidose vial containing 22.8 million units per 3.8 mL)
- Solution for injection 25 million units (10 mg/mL multidose vial containing 32 million units per 3.2 mL)


Inhibition of virus replication in virus-infected cells, and suppression of cell proliferation, and immunomodulating activities such as enhancement of phagocytic activity of macrophages and augmentation of specific cytotoxicity of lymphocytes for target cells.

Slideshow: The ABC's of Hepatitis: Get to Know This Viral Disease



The T max is 3 to 12 h (IM and subcutaneous) and 30 min (IV). The C max is approximately 18 to 116 units/mL (IM and subcutaneous) and 135 to 273 units/mL (IV).


The kidney may be the main site for catabolism.


The elimination t ½ is approximately 2 to 3 h.

Indications and Usage

Hairy cell leukemia; condylomata acuminata; AIDS-related Kaposi sarcoma; chronic hepatitis B; chronic hepatitis C; malignant melanoma; follicular non-Hodgkin lymphoma.

Unlabeled Uses

Treatment of angiomatous disorders; mycosis fungoides; ovarian and cervical carcinoma; renal cell carcinoma; basal and squamous cell skin cancer; bladder tumor (local use for superficial tumors); chronic myelogenous leukemia; cutaneous T-cell lymphoma; non-Hodgkin lymphoma; multiple myeloma; carcinoid tumor; papilloma viruses; West Nile virus infection.


Autoimmune hepatitis; decompensated liver disease. Additional contraindications when given in combination with ribavirin are pregnancy; men whose partners are pregnant; patients with hemoglobinopathies (eg, thalassemia major, sickle cell anemia); CrCl less than 50 mL/min; hypersensitivity to any component of the product.

Dosage and Administration

AIDS-Related Kaposi Sarcoma

IM or Subcutaneous 30 million units/m 2 per dose 3 times/wk until disease progression or maximal response has been achieved after 16 wk of treatment. Dose reduction is frequently required.

Dosage adjustment

1) Reduce interferon alfa-2b dose 50% or withhold for severe adverse reactions. 2) Resume treatment at a reduced dose if severe adverse reactions subside with dose interruption. 3) Permanently discontinue interferon alfa-2b if severe adverse reactions persist or if they recur in patients receiving a reduced dose.

Chronic Hepatitis B

IM or Subcutaneous 30 to 35 million units per wk, either as 5 million units daily or 10 million units 3 times/wk for 16 wk.


IM or Subcutaneous 3 million units/m 2 3 times/wk for the first wk followed by 6 million units/m 2 3 times/wk (max, 10 million units 3 times/wk) subcutaneously for 16 to 24 wk.

Dosage adjustment

1) If severe adverse reactions or laboratory abnormalities develop during interferon alfa-2b therapy, modify the dose (reduce by 50%) or discontinue if appropriate, until the adverse reactions subside. If intolerance persists after dose adjustment, discontinue interferon alfa-2b. 2) For patients with decreases in WBC, granulocyte count or platelet count, reduce the interferon alfa-2b dose 50% if the WBC count is less than 1.5 × 10 9 /L, or if the granulocyte count is less than 0.75 × 10 9 /L, or if the platelet count is less than 50 × 10 9 /L. Permanently discontinue interferon alfa-2b is the WBC count is less than 1 × 10 9 /L, or if the granulocyte count is less than 0.5 × 10 9 /L, or if the platelet count is less than 25 × 10 9 /L.

Chronic Hepatitis C

IM or Subcutaneous 3 million units 3 times/wk in patients tolerating therapy with normalization of ALT at 16 wk of treatment. Extend therapy to 18 to 24 months at 3 million units 3 times/wk to improve the sustained response rate. Consider discontinuing therapy in patients who do not normalize their ALT or who have persistently high levels of hepatitis C virus RNA after 16 wk.

Dosage adjustment

If severe adverse reactions develop during interferon alfa-2b treatment, modify the dose (reduce 50%) or temporarily discontinue therapy until the adverse reactions abate. If intolerance persists after dose adjustment, discontinue interferon alfa-2b.

Condylomata Acuminata

Intralesionally 1 million units/lesion in a max of 5 lesions in a single course. Lesions should be injected 3 times weekly on alternate days for 3 wk. An additional course may be administered at 12 to 16 wk.

Follicular Lymphoma

Subcutaneous 5 million units 3 times/wk for up to 18 months in combination with other antineoplastic therapy.

Dosage adjustment

1) Myelosuppressive drug doses were reduced when an alfa interferon was added to the regimen. 2) Delay chemotherapy cycle if neutrophil count was less than 1,500/mm 3 or platelet count was less than 75,000/m 3 . 3) Permanently discontinue interferon alfa-2b if AST exceeds 5 times the ULN or serum creatinine exceeds 2 mg/dL. 4) Withhold interferon alfa-2b for a neutrophil count less than 1,000/mm 3 or a platelet count less than 50,000/mm 3 . 5) Reduce the interferon alfa-2b dose by 50% for a neutrophil count greater than 1,000/m 3 but less than 1,500/mm 3 . Reescalate the interferon alfa-2b to the starting dose after resolution of hematologic toxicity.

Hairy Cell Leukemia

IM or Subcutaneous 2 million units (million units)/m 2 3 times/wk for up to 6 months. Patients with platelet counts of less than 50,000/mm 3 should receive the drug by subcutaneous administration and not IM.

Dosage adjustment

1) If severe adverse reactions develop, modify the dosage (50% reduction) or temporarily withhold therapy until adverse reactions subside and then resume the dosage at 50%. 2) If severe adverse reactions persist or recur following dosage adjustment, permanently discontinue interferon alfa-2b. 3) Discontinue interferon alfa-2b if disease progresses or if there is failure to respond after 6 months of treatment.

Malignant Melanoma



20 million units/m 2 infused over 20 minutes, 5 consecutive days/wk, for 4 wk.


Subcutaneous administration of 10 million units/m 2 3 times/wk for 48 wk.

Dosage adjustment

Withhold treatment if severe adverse reactions, including granulocyte counts above 250 mm 3 but less than 500 mm 3 or ALT/AST more than 5 to 10 times ULN, until adverse reactions subside. Restart treatment at 50% the previous dose. Discontinue treatment for: 1) toxicity does not subside after withholding the drug; 2) severe adverse reactions that recur in patients receiving reduced doses; 3) granulocyte count less than 250 mm 3 or ALT/AST of more than 10 times ULN.


Store powder or solution for injection at 36° to 46°F. After reconstituting the powder, the solution should be used immediately, but may be stored up to 24 h at 36° to 46°F.

Drug Interactions


Interferon alfa-2b may inhibit hepatic metabolism of theophylline, leading to increased theophylline serum concentrations.


There may be synergistic adverse reactions with interferon alfa-2b and zidovudine.

Laboratory Test Interactions

A transient increase in ALT can occur and is more frequent in responders.

Adverse Reactions

Since the dose and duration of treatment vary according to the condition being treated, the incidence and severity of the following adverse reactions vary considerably with the treatment protocol.


Hypertension (9%); angina, arrhythmia, atrial fibrillation, bradycardia, cardiac failure, cardiomegaly, cardiomyopathy, coronary artery disorder, extrasystoles, heart valve disorder, hematoma, hypotension, palpitations, phlebitis, postural hypotension, pulmonary embolism, Raynaud disease, tachycardia, thrombosis, varicose veins (less than 5%).


Fatigue (96%); asthenia (63%); headache (62%); depression (40%); somnolence (33%); dizziness (24%); irritability (22%); paresthesia (21%); amnesia, impaired concentration, malaise (14%); confusion, insomnia (12%); hypoesthesia (10%); anxiety (9%), vertigo (8%); agitation (7%); decreased libido (5%); nervousness (3%); abnormal coordination, abnormal dreaming, abnormal gait, abnormal thinking, aggravated depression, aggressive reaction, alcohol intolerance, apathy, aphasia, ataxia, Bell's palsy, CNS dysfunction, coma, convulsions, delirium, dysphonia, emotional lability, extrapyramidal disorder, feeling of ebriety, flushing, hot flashes, hyperesthesia, hyperkinesia, hypertonia, hypokinesia, impaired consciousness, loss of consciousness, manic depression, manic reaction, migraine, neuralgia, neuritis, neuropathy, neurosis, paresis, paroniria, parosmia, personality disorder, polyneuropathy, psychosis, speech disorder, stroke, suicidal ideation, suicide attempt, syncope, tremor, twitching (less than 5%).


Alopecia (38%); rash (25%); increased sweating (21%); pruritus (11%); dry skin (10%); dermatitis (8%); purpura (5%); facial edema (5% or less); abnormal hair texture, acne, cellulitis, cyanosis of the hand, cold and clammy skin, dermatitis lichenoides, eczema, epidermal necrolysis, erythema, erythema nodosum, folliculitis, increased hair growth, lacrimal gland disorder, lacrimation, lipoma, maculopapular rash, melanosis, nail disorders, nonherpetic cold sores, pallor, peripheral ischemia, photosensitivity, pruritus genital, psoriasis, psoriasis aggravated, rash erythematous, sebaceous cyst, skin depigmentation, skin discoloration, skin nodule, urticaria, vitiligo (less than 5%).


Pharyngitis (31%); earache, laryngitis, periorbital edema, tonsillitis, tracheitis (5% or less); abnormal vision, blurred vision, conjunctivitis, diplopia, dry eyes, eye pain, hearing disorder, hearing impairment, labyrinth disorder, otitis media, nystagmus, photophobia, sty, rhinitis, rhinorrhea, tinnitus (less than 5%).


Anorexia (69%); nausea (66%); diarrhea (45%); vomiting (32%); dry mouth (28%); taste alteration (24%); abdominal pain (23%); constipation, gingivitis (14%); loose stools (10%); dyspepsia (8%); GI disorder (7%); abdominal ascites, abdominal distension, colitis, dysphagia, eructation, esophagitis, flatulence, gallstones, gastric ulcer, gastritis, gastroenteritis, GI hemorrhage, GI mucosal discoloration, gingival bleeding, gum hyperplasia, halitosis, hemorrhoids, increased appetite, increased salivation, intestinal disorder, melena, mouth ulceration, mucositis, oral hemorrhage, oral leukoplakia, rectal bleeding after stool, rectal hemorrhage, stomatitis, stomatitis ulcerative, taste loss, tongue disorder, tooth disorder (less than 5%).


Hyperglycemia (5% or less); aggravation of diabetes mellitus, goiter, gynecomastia, hyperthyroidism; hypertriglyceridemia, hypothyroidism, virilism (less than 5%).


Amenorrhea (12%); polyuria (10%); UTI (5%); scrotal/penile edema (5% or less); albumin/protein in urine, cystitis, dysmenorrhea, dysuria, genital pruritis, hematuria, impotence, incontinence, increased BUN, leukorrhea, menorrhagia, menstrual irregularity, mictruition disorder, micturition frequency, nocturia, pelvic pain, penis disorder, renal function impairment, sexual dysfunction, uterine bleeding, vaginal dryness (less than 5%).


Neutropenia (92%); anemia (22%); thrombocytopenia (10%); lymphadenitis, lymphadenopathy, mastitis (5% or less); hematologic reactions including granulocytopenia, hemolytic anemia, hypochromic anemia, leukopenia, lymphocytosis, thrombocytopenic purpura (5% or less).


Increased AST (63%); right upper quadrant pain (15%); abnormal liver function tests, biliary pain, bilirubinemia, hepatitis, increased lactate dehydrogenase, increased transaminases (ALT/AST), jaundice, (less than 5%); hepatic encephalopathy, hepatic failure, death (rare).


Injection-site reactions including burning, bleeding, itching, pain (5% or less).


Weight decrease (13%); dehydration, hypercalcemia, thirst, weight increase (5% or less).


Myalgia (75%); rigors (42%); musculoskeletal pain (21%); arthralgia, back pain (19%); arteritis, arthritis, arthritis aggravated, arthrosis, bone disorder, bone pain, carpal tunnel syndrome, hyporeflexia, leg cramps, muscle atrophy, muscle weakness, polyarteritis nodosa, rheumatoid arthritis, spondylitis, tendonitis (less than 5%).


Dyspnea (34%); coughing (31%); sinusitis (21%); nonproductive cough (14%); bronchitis, nasal congestion (10%); epistaxis (7%); asthma, bronchospasm, cyanosis, hemoptysis, hypoventilation, lung fibrosis, orthopnea, pleural effusion, pleural pain, pneumonia, pneumonitis, pneumothorax, rales, respiratory disorder, respiratory insufficiency, sneezing, upper respiratory tract infection, wheezing (5% or less).


Fever (94%); influenza-like symptoms (79%); chills (54%); chest pain (28%); pain (18%); moniliasis (17%); nonspecific infection, viral infection (7%); peripheral edema (6%); herpes simplex (5%); allergic reaction, cachexia, edema, hernia, mastitis, nonspecific inflammation, superficial phlebitis, weakness (5% or less); abscess, bacterial infection, fungal infection, hemophilus herpes zoster infection, hyperthermia, parasitic infection, sepsis, substernal chest pain, trichomonas (less than 5%).



Neuropsychiatric, autoimmune, ischemic, and infectious disorders

Interferons may cause or aggravate fatal or life-threatening disorders of this nature. Persistent severe or worsening signs or symptoms may necessitate discontinuation of therapy. Closely monitor patients with periodic clinical and laboratory evaluations.


Monitor CBCs prior to treatment and routinely during therapy. The following laboratory tests are recommended prior to treatment and periodically thereafter: standard hematologic tests (including hemoglobin, complete and differential WBCs, and platelet counts), blood chemistries (including electrolytes, liver function, and TSH). Patients with preexisting cardiac abnormalities or who are in the advanced stages of cancer should have ECG taken prior to and during treatment. Baseline chest X-rays are recommended and should be repeated as indicated. In patients with malignant melanoma, monitor differential WBC count and liver function weekly during induction of therapy and monthly during maintenance therapy. Mild to moderate leukopenia and elevated AST levels can occur with intralesional therapy; therefore, consider monitoring of these laboratory parameters.


Category C .


Undetermined. Discontinue breast-feeding or the drug.


Safety and efficacy in children not established for indications other than chronic hepatitis B or C.

Chronic hepatitis B

Safety and efficacy not established in children younger than 1 yr of age.

Chronic hepatitis C

Safety and efficacy not established in children younger than 3 yr of age.


Use with caution because of the greater frequency of decreased hepatic, renal, bone marrow, or cardiac function, and of concomitant diseases or other drug therapy. Because elderly patients often have decreased renal function, carefully monitor patients during treatment and adjust dose based on symptoms and laboratory abnormalities.


Acute serious hypersensitivity reactions (eg, anaphylaxis, angioedema, bronchoconstriction, urticaria) have been observed in treated patients; if an acute reaction develops, discontinue the drug immediately and institute appropriate medical therapy.

Hepatic Function

Do not treat patients with decompensated liver disease, autoimmune hepatitis, history of autoimmune disease, or immunosuppressed transplant recipients. Worsening liver disease, including jaundice, hepatic encephalopathy, hepatic failure, and death, have occurred following therapy. Discontinue therapy for any patient developing signs and symptoms of liver failure.

Autoimmune disorders

Rare cases of autoimmune disease, including thrombocytopenia, vasculitis, Raynaud phenomenon, rheumatoid arthritis, lupus erythematosus, and rhabdomyolysis, have been reported.

Bone marrow toxicity

Severe cytopenias, including aplastic anemia, may occur as a result of bone marrow suppression.

CV disorder

Use with caution in patients with history of CV disorder.

Cerebrovascular disorder

Ischemic and hemorrhagic cerebrovascular events have been reported.

Endocrine disorders

Hyperthyroid or hypothyroid abnormalities may occur.

GI disorders

Fatal hepatotoxicity has been reported.


Because interferon alfa-2b contains albumin, a derivative of human blood, there is a risk of transmitting infectious agents (eg, viruses), including Creutzfeldt-Jakob disease.

Neuropsychiatric disorder

Depression and suicidal behavior, including suicidal ideation, suicide attempts, and completed suicides, have been reported.

Ophthalmic disorders

Decrease or loss of vision, retinopathy, including macular edema, retinal artery or vein thrombosis, retinal hemorrhages and cotton wool spots, optic neuritis, and papilledema, may occur or be aggravated by treatment.

Pulmonary disorders

Pulmonary infiltrates, pneumonitis, and pneumonia, including death, have been reported.


Elevated triglyceride levels can occur.



Hemorrhage, hepatic enzyme abnormalities, MI, renal failure.

Patient Information

  • Photosensitivity may occur; therefore, caution patients to take protective measures (eg, use sunscreens, wear protective clothing) against exposure to ultraviolet light or sunlight until tolerance is determined.
  • May cause drowsiness or dizziness.
  • Instruct patients to notify health care provider if hives, itching, tightness in the chest, cough, difficulty breathing, visual problems, wheezing, low blood pressure, or light-headedness occurs.
  • Contraceptive measures are recommended during therapy with interferon alfa-2b. Notify health care provider immediately if pregnancy is suspected.
  • Store in the refrigerator at 2° to 8°C (36° to 46°F). Do not freeze or shake.
  • Do not change brands of interferon; changes in dosage may be necessary.
  • The most common adverse reactions are flu-like symptoms, such as fever, headache, fatigue, anorexia, nausea, and vomiting. These appear to decrease in severity as treatment continues. Some of these flu-like symptoms may be minimized by bedtime doses. Use antipyretics to prevent or partially alleviate fever and headache.
  • Hydrate patients well, especially during the initial stages of treatment.

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