Pegasys 90 and 180 micrograms – peginterferon alfa-2a for hepatitis B and C, polycythaemia vera and thrombocythaemia

Pegasys® contains peginterferon alfa-2a – a long-acting interferon, a protein that modifies the response of the immune system and helps the body fight viral infections and the growth of certain cells. It is injected under the skin, usually once a week.

It is used to treat chronic hepatitis B and chronic hepatitis C (in adults and, under certain conditions, in children) and rare bone marrow diseases – polycythaemia vera and essential thrombocythaemia in adults. In Serbia it is authorised as a solution for injection in a pre-filled syringe of 90 micrograms and 180 micrograms.

What is Pegasys used for and how should it be used correctly?

Key information about the medicine

What is Pegasys used for?

• Polycythaemia vera and essential thrombocythaemia in adults – rare types of cancer in which the bone marrow produces too many red and white blood cells and platelets; Pegasys is used alone.
• Chronic hepatitis B in adults (HBeAg-positive or HBeAg-negative, with compensated liver disease) and in children and adolescents aged 3 and over (HBeAg-positive, without cirrhosis); usually used alone.
• Chronic hepatitis C in adults with compensated liver disease, in combination with other medicines, and in previously untreated children and adolescents aged 5 and over, in combination with ribavirin.

How is Pegasys used and dosed?

The exact dose and duration of treatment are decided by the doctor; the dose may be changed during treatment. Do not exceed the recommended dose.

• The medicine is injected with a short needle into the fatty tissue under the skin of the abdomen or thigh (avoiding the navel and waistline), changing the site each time; the injection is usually given at bedtime.
• Before injecting, let the solution reach room temperature (or warm the syringe in your hands) and check that it is clear.
• If you inject yourself, a doctor or nurse will train you; the syringe, needle and materials are for single use and are disposed of safely in a closed container.

Special patient groups

• Children: the medicine must not be given to children under 3 years, premature babies or newborns (benzyl alcohol). Use is limited to children with hepatitis B aged 3 and over and hepatitis C aged 5 and over; it is not given to children for polycythaemia vera or essential thrombocythaemia. A child's growth and development may be slowed during treatment.
• Elderly patients: according to the summary of product characteristics, no dose adjustment is necessary.
• Impaired kidney function: no dose change in mild and moderate impairment; in severe impairment or end-stage kidney disease 135 micrograms once a week is recommended.
• Impaired liver function: in compensated cirrhosis (Child-Pugh A) the medicine is effective and safe; in decompensated cirrhosis it is contraindicated.

Contraindications – when the medicine must not be used

• allergy to peginterferon alfa-2a, any interferon or any of the excipients;
• previous heart attack or hospital stay for severe chest pain in the last 6 months;
• current or past autoimmune disease (e.g. rheumatoid arthritis, psoriasis, inflammatory bowel disease);
• thyroid disease not controlled with medicines;
• advanced liver disease with impaired function (e.g. jaundice);
• a child under 3 years; a child who has had serious psychiatric conditions (severe depression, suicidal thoughts);
• co-infection with hepatitis C virus and HIV with impaired liver function;
• concomitant treatment with telbivudine.

Precautions and warnings

• past severe nervous or mental disorders, depression or alcohol or drug dependence;
• psoriasis (may worsen), liver problems other than hepatitis B or C, anaemia, liver or kidney transplantation;
• diabetes or high blood pressure – the doctor may ask for an eye examination; report any changes in vision;
• symptoms of a cold or respiratory infection (cough, fever, breathing problems) – the risk of infections may be increased during treatment;
• signs of bleeding or unusual bruising, symptoms of a severe allergic reaction;
• symptoms of Vogt-Koyanagi-Harada syndrome (stiff neck, headache, loss of hair or skin colour, blurred vision, ringing in the ears);
• with ribavirin, dental and gum disorders have been reported, and dry mouth can damage the teeth and mucosa – brush your teeth twice a day and see your dentist regularly; rinse your mouth thoroughly after vomiting;
• during treatment the doctor regularly checks blood counts, liver function, blood sugar and other tests;
• the medicine contains benzyl alcohol (5 mg per syringe), which may cause allergic reactions and may accumulate in the body in liver or kidney disease, pregnancy and breast-feeding, as well as polysorbate 80.

Interactions with other medicines

• telbivudine (hepatitis B) – the combination is contraindicated because of an increased risk of peripheral neuropathy (numbness, tingling, burning in the hands and feet);
• asthma medicines – your asthma treatment may need to be changed;
• anti-HIV therapy (HAART) – with Pegasys and ribavirin the risk of lactic acidosis and worsening liver function increases; zidovudine with ribavirin and interferons increases the risk of anaemia;
• azathioprine with ribavirin and peginterferon – increased risk of serious blood disorders;
• also read the leaflets of all medicines used in combination (e.g. ribavirin).

Pregnancy and breast-feeding

• Pregnancy: consult your doctor. With ribavirin: women must have a negative pregnancy test before, every month during and for 4 months after treatment and use effective contraception throughout; men use condoms, and the female partner has a pregnancy test every month during and for 7 months after treatment, with effective contraception.
• Breast-feeding: it is not known whether the medicine passes into breast milk – do not breast-feed during treatment with Pegasys.

Driving and using machines

• Do not drive or use machines if you feel sleepy, tired or confused during treatment.

Possible side effects

The frequencies listed refer to the combination of Pegasys and ribavirin; when Pegasys is used alone in hepatitis B or C, some side effects are less likely.

• Contact your doctor immediately: depression, suicidal thoughts or aggressive behaviour; severe chest pain, persistent cough, irregular heartbeat, difficulty breathing, confusion, severe abdominal pain, black stools, heavy nosebleed, fever or chills, vision problems.
• Very common: loss of appetite; feeling depressed, anxiety, insomnia, headache, difficulty concentrating, dizziness; cough, shortness of breath; diarrhoea, nausea, abdominal pain; hair loss, itching, dermatitis, dry skin; joint and muscle pain; fever, weakness, fatigue, shaking, chills, pain, irritation at the injection site, irritability.
• Common: fungal, viral and bacterial infections (including herpes and oral thrush); low platelet count, anaemia; overactive or underactive thyroid; mood changes, nervousness, poor memory, migraine, numbness, tremor, taste changes; blurred vision, dry eyes; fast heartbeat, swelling; nosebleed, dry throat; vomiting, mouth ulcers, bleeding gums, dry mouth, weight loss; rash, increased sweating, psoriasis, eczema, sensitivity to sunlight; back and bone pain, muscle cramps; flu-like illness, thirst.
• Uncommon and rare: lung and skin infection, diabetes, dehydration, hallucinations, peripheral neuropathy, retinal bleeding, hearing loss, high blood pressure, gastrointestinal bleeding, liver dysfunction; rarely severe allergic reactions, autoimmune diseases, psychoses, seizures, heart attack and heart failure, interstitial pneumonia, pancreatitis, kidney failure.
• Very rare and not known: aplastic anaemia, thrombocytopenic purpura, loss of vision, severe skin reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis), Vogt-Koyanagi-Harada disease, rejection of a transplanted liver or kidney, mania and bipolar disorder, stroke, pulmonary arterial hypertension.

Overdose, missed dose and stopping treatment

• Overdose: contact your doctor or pharmacist immediately.
• Missed dose – 1 or 2 days late: inject the dose as soon as possible and the next one on your usual day.
• Missed dose – 3 to 5 days late: inject the dose as soon as possible, then every 5 days until you are back on your usual day of the week.
• Missed dose – 6 days late: wait one day and inject on your usual day.
• Never take a double dose. Use the treatment for as long as the doctor has prescribed.

Related information

For monitoring body temperature during treatment, see also the category Digital thermometers – products from this category do not replace the medicine prescribed for you.

Composition, pack and manufacturer

• Active substance: peginterferon alfa-2a – 90 micrograms or 180 micrograms in 0.5 mL of solution (one pre-filled syringe).
• Excipients: sodium chloride, polysorbate 80, benzyl alcohol, sodium acetate, acetic acid, water for injections.
• Pack: carton with 1 pre-filled syringe and 1 sterile needle for subcutaneous use.
• Marketing authorisation holder: Evropa Lek Pharma d.o.o. Beograd, Bore Stankovića 2, Belgrade; manufacturer: LOBA Biotech GmbH, Fehrgasse 7, Fischamend, Austria.
• Authorisations: 002743464 2024 of 01.08.2025 (180 micrograms) and 000283476 2025 of 02.10.2025 (90 micrograms).

Storage

• Store in a refrigerator (2 °C – 8 °C). Do not freeze.
• Keep the syringe in the original carton to protect from light.
• Do not use if the syringe or needle is damaged, or if the solution is cloudy, contains particles or is not colourless to light yellow.
• Keep out of the sight and reach of children. Return unused medicines to a pharmacy that collects them.

Frequently asked questions

How often is Pegasys given?

Usually once a week, by injection under the skin of the abdomen or thigh, most often at bedtime. In polycythaemia vera and essential thrombocythaemia the doctor may adjust the dose or extend the interval between doses.

What should I do if I forget my weekly injection?

If you remember 1–2 days late, inject straight away and continue on your usual day. If 3–5 days have passed, inject straight away and then every 5 days until you are back on your day. If 6 days have passed, wait a day and inject on your usual day. Never give a double dose.

Is it normal to have flu-like symptoms after the injection?

Fever, shaking, chills, fatigue and muscle and joint pain are very common side effects. If the fever is high or accompanied by chills, cough or difficulty breathing, contact your doctor, as the risk of infections is higher during treatment.

Can children use Pegasys?

Only children with chronic hepatitis B aged 3 and over and chronic hepatitis C aged 5 and over, at a dose based on height and body weight. It must not be given to children under 3 years because it contains benzyl alcohol.

Sources

• ALIMS – Package leaflet Pegasys 90 and 180 micrograms (PIL, Serbian; 180 microgram authorisation)
• ALIMS – Summary of product characteristics Pegasys (SmPC, Serbian; 180 microgram authorisation)
• ALIMS – Package leaflet Pegasys (PIL, Serbian; 90 microgram authorisation)
• ALIMS – Summary of product characteristics Pegasys (SmPC, Serbian; 90 microgram authorisation)

Sources checked on: 25.10.2026.