Interferon Gamma-1b

Pronunciation: (IN-ter-FEER-on)
Class: Immunomodulator

Trade Names

Actimmune
- Injection 100 mcg (2 million units) per 0.5 mL

Pharmacology

Produces potent phagocyte-activating effects, including generation of toxic oxygen metabolites within phagocytes, which mediate killing of microorganisms. Activities include enhancement of oxidative metabolism of macrophages, enhancement of antibody-dependent cellular cytotoxicity, activation of natural killer cells, and the expression of Fc receptors and major histocompatibility antigens.

Pharmacokinetics

Absorption

The apparent bioavailability is more than 89% (IM, subcutaneous). C _max is 1.5 ng/mL (IM) and 0.6 ng/mL (subcutaneous). T _max is approximately 4 h (IM) and 7 h (subcutaneous).

Elimination

Mean t _½ is 38 min (IV), 2.9 h (IM), and 5.9 h (subcutaneous).

Special Populations

Renal/Hepatic function impairment

Data not available.

Indications and Usage

Reducing the frequency and severity of serious infections associated with chronic granulomatous disease; delaying time to disease progression in severe malignant osteopetrosis.

Contraindications

Hypersensitivity to Escherichia coli –derived products, interferon-gamma, or any component of the product.

Dosage and Administration

Adults and Children

Subcutaneous 50 mcg/m ² (1 million units/m ² ) if body surface area is more than 0.5 m ² or 1.5 mcg/kg/dose if body surface area is 0.5 m ² or less. Administer 3 times/wk (eg, Monday, Wednesday, Friday) into right or left deltoid or anterior thigh. If severe adverse reactions develop, reduce dosage by 50% or interrupt therapy until those reactions subside.

General Advice

• Visually inspect for particulate matter or discoloration prior to administration.
• Formulation does not contain preservative and is suitable for a single use only.
• Do not mix with other drugs in the same syringe.

Storage/Stability

Store under refrigeration at 36° to 46°F. Do not leave at room temperature for a total time exceeding 12 h prior to use. Do not freeze. Do not shake (avoid excessive or vigorous agitation).

Drug Interactions

Myelosuppressive agents

Additive neutropenic effects are possible.

Laboratory Test Interactions

None well documented.

Adverse Reactions

CNS

Headache (33%); fatigue (14%); depression (3%); confusion, disorientation, gait disturbance, hallucinations, parkinsonian symptoms, seizure.

Cardiovascular

Heart block, heart failure, hypotension, MI, syncope, tachyarrhythmia, transient ischemic attacks.

Dermatologic

Rash (17%); exacerbation of dermatomyositis; atopic dermatitis, Stevens-Johnson syndrome, urticaria (postmarketing).

GI

Diarrhea (14%); vomiting (13%); nausea (10%); GI bleeding, pancreatitis (including pancreatitis with fatal outcome); granulomatous colitis (postmarketing).

Genitourinary

Proteinuria, reversible renal insufficiency.

Hematologic

Deep venous thrombosis, pulmonary embolism, thrombocytopenia.

Hepatic

Hepatic function impairment; hepatomegaly (postmarketing).

Lab Tests

Elevated ALT and AST, neutropenia; elevated alkaline phosphatase, hypokalemia (postmarketing).

Local

Injection-site erythema or tenderness (14%).

Metabolic-Nutritional

Hyperglycemia, hypertriglyceridemia, hyponatremia.

Musculoskeletal

Myalgia (6%); arthralgia, back pain (2%).

Respiratory

Bronchospasm, interstitial pneumonitis, tachypnea.

Miscellaneous

Fever (52%); chills (14%); abdominal pain (8%); chest discomfort, increased autoantibodies, lupus-like syndrome.

Precautions

Monitor Hematologic tests (including CBC, differential and platelet counts), blood chemistries (including renal and liver function tests), and urinalysis should be done prior to therapy and at 3-mo intervals during treatment. Patients starting treatment before 1 yr of age should receive monthly liver function assessment.

Pregnancy

Category C .

Lactation

Undetermined.

Hypersensitivity

Acute serious hypersensitivity reactions have been reported.

Special Risk Patients

Exercise caution in patients with seizure disorders, compromised CNS function, and myelosuppression.

Cardiac Disease

Use with caution in patients with preexisting cardiac conditions, including ischemia, congestive heart failure, or arrythmia.

Hepatotoxicity

Elevations of AST and/or ALT, up to 25-fold, have occurred. The incidence appears to be greater in children younger than 1 yr of age compared with older children.

Overdosage

Symptoms

CNS reactions, including decreased mental status, dizziness, and gait disturbance; elevated hepatic enzymes and triglycerides; reversible neutropenia; thrombocytopenia.

Patient Information

• Stress importance of returning for follow-up blood tests.
• Teach infection control measures, bleeding precautions, and energy-conservation measures.
• Caution patient to use safety precautions and not to perform activities that require mental alertness if decreased mental status or dizziness occur.
• Advise patient to take medication at bedtime if flu-like symptoms occur and to use acetaminophen as needed.
• Explain importance of adequate hydration.
• Teach patient or family to store, prepare, and administer drug subcutaneously.
• Provide puncture-resistant container for disposal of used syringes and needles.
• Instruct patient to report the following symptoms to health care provider: anxiety, breast pain, chest pain, confusion, cysts, difficulty breathing, dyspnea, fever, fluid retention, flu-like symptoms, frequent urination, hair loss, headache, high blood pressure, joint and muscle aches, laryngitis, menstrual problems, migraine headaches, noisy breathing, pain at injection site, pelvic pain, pounding in chest, seizures, sinus infection, sleeplessness, sweating, swollen ankles.

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