INTERFERON ALFA-2B

INTERFERON ALFA-2b
(in-ter-feer'on)
Intron A
Classifications: immunomodulator; interferon; antineoplastic;
Therapeutic: immunomodulator; interferon; antineoplastic
Prototype: Interferon alfa-2a
Pregnancy Category: C

Availability

5 million IU, 10 million IU, 18 million IU, 25 million IU, 50 million IU vials

Action

Interferon (IFN) alfa-2b, one of 4 types of alpha interferons, is a highly purified protein and natural product of human leukocytes within 4–6 h after viral stimulation. Produced by recombinant DNA technology (rIFN-A). Antiviral action: Reprograms virus-infected cells to inhibit various stages of virus replication. Antitumor action: Suppresses cell proliferation. Immunomodulating action: Enhances phagocytic activity of macrophages and augments specific cytotoxicity of lymphocytes for target cells. The immune system and the interferon system of defense are complementary.

Therapeutic Effect

Has a broad spectrum of antiviral, cytotoxic, and immunomodulating activity (i.e., favorably adjusts immune system to better combat foreign invasion of antigens, cancers, and viruses).

Uses

Hairy cell leukemia in splenectomized and non-splenectomized patients ≥18 y, chronic hepatitis B or C, malignant melanoma, condylomata acuminata, AIDS-related Kaposi's sarcoma.

Unlabeled Uses

Multiple sclerosis, condylomata acuminata.

Contraindications

Hypersensitivity to interferon alfa-2b or to any components of the product; colitis; pancreatitis; neonates, pregnancy (category C), lactation.

Cautious Use

Severe, preexisting cardiac, renal, or hepatic disease; pulmonary disease (e.g., COPD); diabetes mellitus patients prone to ketoacidosis; coagulation disorders; severe myelosuppression; recent MI; previous dysrhythmias.

Route & Dosage

Hairy Cell Leukemia
Adult: IM/SC 2 million U/m² 3 times/wk

Kaposi's Sarcoma
Adult: IM/SC 30 million U/m² 3 times/wk

Condylomata Acuminata
Adult: IM/SC 1 million U/m² 3 times/wk

Chronic Hepatitis B or C
Adult: SC 3 million U 3 times/wk x 18–24 mo

Malignant Melanoma
Adult: IV 20 million IU/m² daily for 5 d per wk x 4 wk; maintenance dose is 10 million IU/m² given SC weekly x 48 wk

Renal Impairment
Not removed by dialysis.

Administration

Note: Interferon alfa-2b should be administered under the guidance of a qualified physician.

Subcutaneous/Intramuscular

Reconstitution: The final concentration with the amount of required diluent is determined by the condition being treated (see manufacturer's directions). Inject diluent (bacteriostatic water for injection) into interferon alfa-2b vial; gently agitate solution before withdrawing dose with a sterile syringe.
Make sure reconstituted solution is clear and colorless to light yellow and free of particulate material; discard if there are particles or solution is discolored.
Store vials and reconstituted solutions at 2°–8° C (36°–46° F); remains stable for 1 mo. Discard any remaining drug in reconstituted vials.

Intravenous

PREPARE: IV Infusion: Prepare immediately before use. Select the appropriate number of vials (i.e., 10, 18, or 50 million IU) of recombinant powder for injection and add to each the 1 mL of supplied diluent. Swirl gently to dissolve but do not shake. Further dilute by adding the required dose to 100 mL of NS. The final concentration should be <10 million IU/100 mL.

ADMINISTER: IV Infusion: Infuse over 20 min.

INCOMPATIBILITIES Solution/additive: Dextrose-containing solutions.

Adverse Effects (≥1%)

Body as a Whole: Flu-like syndrome (fever, chills) associated with myalgia and arthralgia, leg cramps. CNS: Depression, nervousness, anxiety, confusion, dizziness, fatigue, somnolence, insomnia, altered mental states, ataxia, tremor, paresthesias, headache. CV: Hypertension, dyspnea, hot flushes. Special Senses: Epistaxis, pharyngitis, sneezing; abnormal vision. GI: Taste alteration, anorexia, weight loss, nausea, vomiting, stomatitis, diarrhea, flatulence. Hematologic: Mild thrombocytopenia, transient granulocytopenia, anemia, neutropenia, leukemia. Skin: Mild pruritus, mild alopecia, rash, dry skin, herpetic eruptions, nonherpetic cold sores, urticaria.

Interactions

Drug: May increase theophylline levels; additive myelosuppression with antineoplastics, zidovudine may increase hematologic toxicity, increase doxorubicin toxicity, increase neurotoxicity with vinblastine. Use with ribavirin increases risk of hemolytic anemia; do not use in combination with ribavirin if Cl_cr <50 mL/min.

Pharmacokinetics

Peak: 6–8 h. Metabolism: In kidneys. Half-Life: 6–7 h.

Nursing Implications

(see INTERFERON ALFA-2A)

Assessment & Drug Effects

Assess hydration status; patient should be well hydrated, especially during initial stage of treatment and if vomiting or diarrhea occurs.
Lab tests: Closely monitor CBC with differential and platelet counts.
Monitor for ecchymoses, petechiae, and bruising.
Assess for flu-like symptoms, which may be relieved by acetaminophen (if prescribed).
Monitor level of GI distress and ability to consume fluids and food.
Monitor mental status and alertness; implement safety precautions if needed.

Patient & Family Education

Learn techniques for reconstitution and administration of drug.
Do NOT change brands of interferon without first consulting the physician.
Note: If flu-like symptoms develop, take acetaminophen as advised by physician and take interferon at bedtime.
Note: Fertile, nonpregnant women need to use effective contraception.
Use caution with hazardous activities until response to drug is known.
Learn about adverse effects and notify physician about those that cause significant discomfort.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

(31)