INTERFERON ALFA-2a
(in-ter-feer'on)
Roferon-A Injection
Classifications: immunomodulator; interferon
Pregnancy Category: C

Availability

3 million IU/mL, 6 million IU/mL, 9 million IU/mL, 36 million IU/mL, 6 million IU/0.5 mL, 9 million IU/0.5 mL injection.

Actions

Interferon (IFN) alfa-2a, one of 4 types of alpha interferon, is a highly purified protein and natural product of human leukocytes within 4–6 h after viral stimulation. Also 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. IFN is species specific but not virus specific; it partially inhibits viral replication and is immediately produced at site of viral entry by any cell; thus, the immune system and the interferon system of defense are complementary.

Therapeutic Effects

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

Uses

To induce hairy cell leukemia remission in splenectomized and nonsplenectomized patients; treatment of hepatitis C, adjunct to surgery for malignant melanoma.

Unlabeled Uses

Chronic hepatitis B virus infection, solid tumors, human papillomavirus (HPV)-associated diseases, AIDS associated Kaposi's sarcoma.

Contraindications

Hypersensitivity to alpha interferons or any component of product and to mouse immunoglobulin. Safe use during pregnancy (category C), lactation, or by children <18 y is not established.

Cautious Use

Cardiac disease or history of cardiac illness, severe cardiac, renal, or hepatic disease; seizure disorders, compromised CNS function; myelosuppression; chickenpox (existing or recent, including recent exposure), herpes zoster.

Route & Dosage

Hairy Cell Leukemia
Adult: SC/IM 3 million U/d for 16–24 wk, may be reduced to 3 times/wk for maintenance therapy

AIDS-related Kaposi's Sarcoma
Adult: SC/IM 36 million U/d for 10–12 wk, may then be reduced to 3 times/wk

Genital and Anal Warts
Adult: Intralesional 1 million U injected in each lesion 3 times/wk on alternate days for 3 wk

Chronic Viral Hepatitis
Adult: SC/IM 1–3 million U/d for 1 wk, then 3 times/wk for 48–52 wk

Administration

Note: IFN should be administered under the guidance of a qualified physician.

Subcutaneous/Intramuscular

Adverse Effects (1%)

Body as a Whole: Flu-like syndrome (fever, chills, myalgia, headache). CNS: Fatigue, dizziness, confusion, paresthesias, lethargy, psychosis, depression, nervousness, forgetfulness. CV: Dyspnea, edema, hypertension, palpitations. GI: Nausea, vomiting, diarrhea, anorexia, abdominal pain, change in taste, mild to moderate hepatotoxicity. Hematologic: Leukopenia, neutropenia, thrombocytopenia, myelosuppression. Skin: Rash, dry skin, pruritus, partial alopecia (eyelash growth increases), urticaria, reactivation of herpes labialis. Respiratory: Dryness or inflammation of oropharynx, coughing. Other: Transient impotence, arthralgia.

Diagnostic Test Interference

Decreased Hgb, Hct; elevated fasting blood sugar, serum phosphorus, serum creatinine, AST, ALT, alkaline phosphatase, LDH; hypocalcemia.

Interactions

Drug: May increase theophylline levels; additive myelosuppression with antineoplastics, zidovudine may increase hematologic toxicity, increase doxorubicin toxicity, increase neurotoxicity with vinblastine. Aldesleukin (IL-2) may potentiate the risk of renal failure.

Pharmacokinetics

Absorption: Well absorbed after IM or SC injection. Peak: 15–60 min IV; 1–8 h IM. Distribution: Widely distributed, concentrating in spleen, kidney, liver, and lung. Metabolism: Metabolized principally in kidney. Half-Life: 5.1 h.

Nursing Implications

Assessment & Drug Effects

Patient & Family Education


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