peginterferon alfa-2b

peginterferon alfa-2b,

a covalent conjugate of recombinant interferon alfa-2b and polyethylene glycol, used in the treatment of chronic infection by hepatitis C virus. It is administered subcutaneously.

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peginterferon alfa-2b

PEG-Intron, PegIntron (UK), ViraferonPeg (UK)

Pharmacologic class: Immunomodulator

Therapeutic class: Immunologic agent

Pregnancy risk category C (monotherapy), X (when given with ribavirin)

FDA Boxed Warning

• Drug may cause or aggravate fatal or life-threatening neuropsychiatric, autoimmune, ischemic, and infectious disorders. Monitor patient closely with periodic clinical and laboratory evaluations. Withdraw drug in patients with persistently severe or worsening signs or symptoms of these conditions. In most cases, these disorders resolve once therapy ends.
• Concurrent use with ribavirin may cause birth defects or fetal death. Use extreme care to avoid pregnancy in female patients and female partners of male patients.

Action

Binds to specific cell-surface membrane receptors, causing suppression of cell proliferation, enhanced phagocytic macrophage activity, and inhibition of viral replication

Availability

Powder for injection with diluent: 50 mcg/0.5-ml vial, 80 mcg/0.5-ml vial, 120 mcg/0.5-ml vial, 150 mcg/0.5-ml vial (Redipen)

⊘Indications and dosages

➣ Chronic hepatitis C virus infection (HCV)

Adults ages 18 and older: For monotherapy, 1 mcg/kg/week subcutaneously for 1 year. When given with ribavirin, 1.5 mcg/kg/week subcutaneously.

Dosage adjustment

• Serious adverse reactions

Contraindications

• Hypersensitivity to drug or its components
• Autoimmune hepatitis
• Decompensated hepatic damage

Precautions

Use cautiously in:
• human immunodeficiency virus, hepatitis B infection
• patients who have failed other interferon alfa therapy
• patients who develop neutralizing antibodies
• organ transplant recipients
• elderly patients
• pregnant or breastfeeding patients
• children.

Administration

• Reconstitute by holding dual-chamber glass cartridge upright with dose button down and pressing two halves of pen together until you hear an audible click. Then gently invert (don't shake) pen to mix solution.
• Discard solution if it is discolored or cloudy or contains particulates.
• To administer, hold pen upright, attach supplied needle, and select appropriate dosage by pulling back on dosing button until dark bands are visible. Then turn button until dark band aligns with correct dose.
• Use reconstituted solution immediately.

Route	Onset	Peak	Duration
Subcut.	Unknown	15-44 hr	Unknown

Adverse reactions

CNS: fatigue, headache, malaise, asthenia, dizziness, insomnia, depression, anxiety, emotional lability, irritability, poor concentration, agitation, nervousness, rigors, suicidal behavior, suicidal or homicidal ideation

CV: hypotension, tachycardia, chest pain, angina pectoris, arrhythmias, cardiomyopathy, myocardial infarction

EENT: vision decrease or loss, retinal artery or vein thrombosis, retinal hemorrhage, cotton-wool spots in visual field, rhinitis, sinusitis, pharyngitis

GI: nausea; vomiting; diarrhea; constipation; abdominal pain; dyspepsia; right upper abdominal quadrant pain; anorexia; dry mouth; ulcerative, hemorrhagic, or ischemic colitis; pancreatitis

GU: menstrual disorder

Hematologic: neutropenia, thrombocytopenia

Hepatic: hepatomegaly

Metabolic: aggravated hypothyroidism or hyperthyroidism

Musculoskeletal: myalgia, arthralgia, musculoskeletal pain

Respiratory: dyspnea, pneumonia, bronchiolitis obliterans, cough, sarcoidosis , pulmonary infiltrates, interstitial pneumonitis, bronchoconstriction

Skin: rash, dry skin, pruritus, sweating, flushing, alopecia

Other: exacerbation or development of autoimmune disorders, injection-site reaction, fever, viral or fungal infection, systemic lupus erythematosus, severe hypersensitivity reactions including angioedema and anaphylaxis

Interactions

Drug-diagnostic tests. Bilirubin, triglycerides, uric acid: increased levels

Glucose, thyroid function tests: decreased or increased levels

Hemoglobin, neutrophils, platelets, white blood cells: decreased levels

Patient monitoring

• Before therapy begins, assess CBC (including platelet count); blood glucose level, and thyroid, kidney, and liver function tests. Continue to monitor at weeks 2, 4, 8, and 12 and then every 6 weeks during therapy (more often if abnormalities occur). Monitor thyroid function tests every 12 weeks.
☞ Assess cardiac and pulmonary status closely. Watch for signs and symptoms of infection and hypersensitivity reactions, including anaphylaxis.
☞ Monitor neurologic status. Stay alert for such behavioral changes as irritability, anxiety, depression, and homicidal or suicidal ideation.
☞ If serious adverse reaction occurs, know that drug will be discontinued or dosages adjusted accordingly.
• Monitor patient for development of diabetes mellitus, hypothyroidism, or hyperthyroidism.
• Be aware that if HCV level remains high after 6 months, drug should be discontinued.

Patient teaching

• Tell patient to take exactly as prescribed. If he misses a dose but remembers it within 2 days, instruct him to take it as soon as possible. However, if more than 2 days have elapsed, advise him to contact prescriber.
• Teach patient or caregiver how to administer injection subcutaneously into thigh or abdomen, if appropriate, and how to properly dispose of equipment.
☞ Advise patient to stop drug and promptly report infection symptoms, such as high fever, easy bruising or bleeding, decreased vision, chest pain, shortness of breath, severe stomach or lower back pain, depression, or suicidal or homicidal thoughts.
• Urge patient to have periodic eye exams.
• Instruct female patient of childbearing age to avoid pregnancy and to use two birth control methods before, during, and up to 6 months after therapy. Instruct male patient to use condoms.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the tests mentioned above.