Home Drug Guide Peginterferon Alfa-2a

Drug Guide

Generic Name

Peginterferon Alfa-2a

Brand Names Pegasys

Classification

Therapeutic: Antiviral and immunomodulator

Pharmacological: Interferon, recombinant

FDA Approved Indications

  • Chronic hepatitis B virus infection
  • Chronic hepatitis C virus infection (in combination with other agents)

Mechanism of Action

Peginterferon Alfa-2a enhances the immune response against viral-infected cells and inhibits viral replication by modulating the immune system and interfering with viral gene expression and replication.

Dosage and Administration

Adult: Usually 180 mcg once weekly by subcutaneous injection. Dosage may vary based on condition and patient response.

Pediatric: Not typically recommended for children.

Geriatric: Use with caution; adjust dose based on tolerability and response.

Renal Impairment: Adjust dose if necessary; monitor renal function.

Hepatic Impairment: Use with caution; hepatic function should be monitored.

Pharmacokinetics

Absorption: Once weekly subcutaneous injection with peak levels in 24-48 hours.

Distribution: Distributed into tissues; large volume of distribution.

Metabolism: Metabolized by proteolytic enzymes; not extensively processed by liver enzymes.

Excretion: Primarily excreted via kidneys.

Half Life: Approximately 40-60 hours.

Contraindications

  • Hypersensitivity to peginterferon alfa-2a or any component of the formulation.
  • Autoimmune hepatitis.
  • Decompensated liver disease.

Precautions

  • Monitor for autoimmune disorders.
  • Use with caution in patients with psychiatric disorders, cardiac disease, or hematologic abnormalities.
  • Pregnancy category C; should only be used if clearly needed during pregnancy; effective contraception recommended during therapy and for 6 months after.

Adverse Reactions - Common

  • Flu-like symptoms (fever, chills, myalgia) (Very common)
  • Fatigue (Common)
  • Headache (Common)
  • Nausea and vomiting (Common)
  • Bone marrow suppression (neutropenia, thrombocytopenia, anemia) (Common)

Adverse Reactions - Serious

  • Neuropsychiatric effects (depression, suicidal ideation) (Uncommon)
  • Autoimmune disorders (thyroiditis, autoimmune hepatitis) (Uncommon)
  • Severe neuropsychiatric symptoms or depression leading to discontinuation (Uncommon)
  • Allergic reactions including anaphylaxis (Rare)

Drug-Drug Interactions

  • Ribavirin, other myelosuppressants, other immunomodulators.

Drug-Food Interactions

  • Limited data; generally no significant food interactions.

Drug-Herb Interactions

  • Potential interactions with herbal supplements affecting immune function; consult with healthcare provider.

Nursing Implications

Assessment: Baseline complete blood count, hepatic function, mental health status, and screening for autoimmune disorders.

Diagnoses:

  • Risk for infection due to myelosuppression
  • Risk for depression or suicidal ideation

Implementation: Administer subcutaneously as prescribed; monitor blood counts, liver function, and mental health throughout therapy.

Evaluation: Assess for efficacy of viral suppression, monitor adverse effects, and adjust dosage as necessary.

Patient/Family Teaching

  • Report flu-like symptoms, depression, suicidal thoughts, or unusual bleeding.
  • Use contraceptives during treatment and for 6 months after.
  • Adherence to injection schedule is essential for effectiveness.
  • Avoid pregnancy during therapy and for 6 months afterward.

Special Considerations

Black Box Warnings:

  • Neuropsychiatric effects, including depression and suicidality.
  • Hepatitis B reactivation in patients with HBV infection undergoing treatment for hepatitis C.

Genetic Factors: Genetic polymorphisms can influence response to therapy.

Lab Test Interference: Can cause transient decreases in blood counts and liver enzymes, monitor regularly.

Overdose Management

Signs/Symptoms: Flu-like symptoms, hematologic abnormalities, neuropsychiatric symptoms.

Treatment: Supportive care; no specific antidote. Discontinue drug and provide symptomatic treatment as needed.

Storage and Handling

Storage: Store refrigerated at 2-8°C (36-46°F). Do not freeze.

Stability: Stable until the expiration date on the label when stored properly.

🛡️ 5 Critical Medication Safety Tips for Nurses

1

Triple-Check High-Risk Medications

Always have another nurse verify insulin, heparin, warfarin, and chemotherapy drugs. These "high-alert" medications cause the most serious errors. Check concentration, dose calculation, and pump settings twice.

2

Know Look-Alike, Sound-Alike Drugs

Common mix-ups: hydromorphone/morphine, Celebrex/Celexa, Zyprexa/Zyrtec. Always use BOTH generic and brand names, read labels twice, and use barcode scanning when available. One wrong letter can be fatal.

3

Assess Before AND After Giving Meds

Check vitals before cardiac meds, pain levels before analgesics, and blood glucose before insulin. Always reassess within 30 minutes to evaluate effectiveness and watch for adverse reactions.

4

Watch for Drug Interactions

Common dangerous combinations: warfarin + aspirin (bleeding), ACE inhibitors + potassium (hyperkalemia), digoxin + diuretics (toxicity). Always check drug interactions before administering new medications.

5

Educate Your Patients

Teach patients medication names, purposes, major side effects, and what to report. Informed patients catch errors and improve compliance. Always encourage questions - an educated patient is a safer patient.

⚡ Remember: When in doubt, don't give it out! It's always safer to double-check than regret later.

⚠️ Medical Disclaimer

This drug guide is for educational purposes only and is NOT intended for clinical use. Always consult current prescribing information, healthcare providers, and institutional protocols before administering any medication. Do not use this information for patient care decisions.