Interferon Alfacon-I

A to Z Drug Facts

 Action These small protein molecules bind to specific cell-surface receptors and initiate complex sequences of intracellular events, including production of enzymes and other products with antiviral, antiproliferative, and immunodulatory effects.

 Indications Treatment of chronic hepatitis C virus (HVC) infection in patients > 18 years with compensated liver disease who have anti-HCV serum antibodies or the presence of HCV RNA. Unlabeled use(s): In conjunction with G-CSF for the treatment of hairy-cell leukemia.

 Contraindications Allergy to alpha-interferons, E. coli-derived products, or to any component of the product.

 Route/Dosage

Initial Therapy

ADULTS: SC 9 mcg 3 times/wk for 24 weeks.

Nonresponders/Relapse

ADULTS: SC 15 mcg 3 times/wk for 6 months if previous interferon therapy was tolerated.

 Interactions None well documented.

 Lab Test Interferences None well documented.

 Adverse Reactions

CV: Hypertension; palpitations. RESP: Upper respiratory infection; cough; dyspnea; bronchitis. CNS: Depression; insomnia; dizziness; paresthesia; hypoesthesia; amnesia; hypertonia; confusion; somnolence; nervousness; anxiety; emotional lability; abnormal thinking; agitation. EENT: Conjunctivitis; eye pain; abnormal vision; tinnitus; earache; otitis; sinusitis; rhinitis; epistaxis; pharyngitis. GI: Abdominal pain; nausea; diarrhea; anorexia; dyspepsia; vomiting; constipation; flatulence; toothache; hemorrhoids; decreased salivation; altered taste. GU: Menstrual disorder; vaginitis; decreased libido; breast pain. HEMA: Leukopenia; granulocytopenia; thrombocytopenia; lymphocytosis. HEPA: Hepatomegaly; liver tenderness. DERM: Alopecia; pruritus; rash; erythema; dry skin. META: Hypothyroidism; hypertriglyceridemia. OTHER: Flu-like symptoms; injection site reactions (eg, erythema, pain, ecchymosis); body, chest, back, limb, neck and skeletal pain; hot flushes; malaise; weakness; edema; allergic reaction; ecchymosis; lymphadenopathy.

 Precautions

Pregnancy: Category C. Lactation: Undetermined. Children: Safety and efficacy in children < 18 yr not established. Suicide/Mental disorders: Do not use in patients with a history of severe psychiatric disorders. Discontinue use in patients developing severe depression, suicidal ideation, or other severe psychiatric disorders. Cardiac disease: Use with caution. Hypertension, supraventricular arrhythmias, chest pain, and MI have been associated with interferon therapies. Bone marrow depression: Use with caution in patients with abnormally low peripheral blood cell counts or who are receiving agents known to cause myelosuppression. Decompensated hepatic disorder: Do not use in patients with decompensated hepatic disease. Discontinue use in patients who develop symptoms of hepatic compensation (eg, jaundice, ascites, coagulopathy, decreased serum albumin). Thyroid disorders: Use has been associated with hypothyroidism requiring supplementation. Autoimmune disease: Interferon alfacon-I should not be used in patients with autoimmune hepatitis and used with caution in patients with other autoimmune disorders. Ophthalmologic disorders: Retinal hemorrhages, cotton wool spots, and retinal artery or vein obstruction have been reported rarely. Fever: May be related to flu-like symptoms associated with therapy. Rule out other possible causes if persistent fever occurs.

 Administration/Storage

• Administer via SC route only.
• Do not administer if particulate matter or discoloration noted.
• May allow solution to reach room temperature before administering.
• If severe adverse reactions develop, dosage adjustment or discontinuation of therapy may be appropriate.
• Use only 1 dose/vial. Do not re-enter vial.
• Discard any unused portions. Do not save unused portions for later administration.
• Store in refrigerator. Do not freeze. Avoid vigorous shaking.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies. Note history of cardiac disease, psychiatric disorders, autoimmune disease or myelosuppressive therapy.
• Ensure that CBC, liver function, and thyroid function tests are done prior to initiating therapy.
• Assess patient for CNS, GI, cardiovascular, hematological, ophthalmic, and dermatologic side effects. If these effects occur, notify physician.
• Assess for flu-like symptoms (eg, fever, rigors, headache, fatigue, arthralgia, myalgia, chills, sweating). If such symptoms occur, administer drug in the evening and give non-narcotic analgesics as prescribed.
• Monitor the following laboratory tests prior to beginning therapy, 2 weeks after initiation of therapy, and periodically thereafter during the 24 weeks of therapy: Platelet count; hemoglobin; absolute neutrophil count; serum creatinine or creatinine clearance; serum albumin; TSH and T4. Following completion of therapy monitor any abnormal test values periodically.
• If patient experiences adverse CNS symptoms, implement safety precautions such as lowering bed, putting side rails up, and supervising ambulation.
• Implement infection control measures if WBC drops; implement bleeding precautions if platelet count drops.
• Withhold therapy if absolute neutrophil count is < 500/mm³ or if platelet count is < 50,000/mm³.
• Withhold temporarily if severe adverse reactions occur. If reaction does not become tolerable, discontinue therapy. Dose reduction from 9 mcg to 7.5 mcg may be necessary following an intolerable adverse event. If adverse reactions continue to occur at reduced dosage, discontinue treatment or reduce dosage further. Decreased efficacy may result from continued treatment at doses < 7.5 mcg. Reduce dose in increments of 3 mcg when using the 15 mcg dose.

 Patient/Family Education

• Explain name, dose, action, and potential side effects of drug. Emphasize that flu-like symptoms are most common. If patient will be administering at home, review “Information for Patients” leaflet with patient. Ensure that the patient understands how to store, prepare, and administer the dose and dispose of used equipment and supplies.
• Stress importance of follow-up blood tests.
• Teach patient infection control and bleeding precautions.
• Advise patient to take medication at bedtime if flu-like symptoms occur and to use non-narcotic analgesics as prescribed.
• Advise patient that drug may cause drowsiness or dizziness and to use caution while driving or performing other activities requiring mental alertness.
• Instruct patient to notify physician if they become pregnant, plan on becoming pregnant, or are breastfeeding.
• Warn patient not to change brands of drug because of differences in manufacturing process, strength, and product type.
• Advise patient to report any of the following: Signs or feelings of depression; persistent fever; sore throat; unusual bleeding or bruising; sudden changes in vision.

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Copyright © 2003 Facts and Comparisons
David S. Tatro
A to Z Drug Facts