Peginterferon alfa-2a for selected hepatitis B cases
Content date: 15 November 2026
A weekly injection that a liver specialist may select as a finite treatment for suitable hepatitis B cases. It needs careful monitoring during and after treatment.
Your next step
Check your written prescription and monitoring plan. If anything is unclear, ask your care team before changing a dose.
Get urgent help: Get immediate help for thoughts of self-harm, severe confusion, sudden vision loss, chest pain, breathing difficulty or major bleeding.
How to use
- The usual adult Pegasys schedule is 180 micrograms under the skin weekly for 48 weeks; the team may adjust this for response or tolerability. Learn injection technique and safe needle disposal, and rotate injection sites. Food does not affect injection timing. If remembered within two days, take the missed dose as directed in the Pegasys leaflet; after that, contact your team. Never double.
Storage
- Pegasys: refrigerate at 2–8°C and protect from light. Do not freeze or shake. If left unrefrigerated or frozen, ask the pharmacist before use; follow your own leaflet’s permitted time outside the refrigerator.
Tests and follow-up
- Blood counts, liver/kidney function, thyroid tests, glucose and HBV DNA are monitored. Assess mood and pregnancy before starting. Blood tests are repeated early and regularly; an eye examination may be needed.
Possible side effects: what to expect
- Not everyone gets side effects. Tiredness, flu-like aches or fever after injections, and injection-site soreness may occur. Plan some rest and ask your team which pain relief suits your liver condition; report severe or persistent symptoms.
- Mood changes, depression, low blood-cell counts and thyroid problems need monitoring. Report mood changes promptly and attend blood tests. Seek immediate help for thoughts of self-harm; finding problems early allows the team to adjust treatment.
Important
- Disclose depression, autoimmune, thyroid or heart disease, and pregnancy plans. This treatment is unsuitable for decompensated liver disease. Review interactions, particularly telbivudine, theophylline and methadone; check before starting any new medicine.
My prescribed plan - complete with the team
Brand / device: ........................ | Dose and how I take or use the medicine: ........................
Next dose: ........................ | Next blood tests: ........................
Team contact: ........................
Brand / device: ........................ | Dose and how I take or use the medicine: ........................
Next dose: ........................ | Next blood tests: ........................
Team contact: ........................
When to get help
Get immediate help for thoughts of self-harm, severe confusion, sudden vision loss, chest pain, breathing difficulty or major bleeding.
Report mood changes, persistent fever, bruising or jaundice the same day, and troublesome persistent symptoms promptly.