Read the Medication Guide and Instructions for Use provided by your pharmacist before you start using peginterferon alfa-2a and each time you get a refill. Ask your health care professional how to prepare and use this medication. If you have any questions, ask your doctor or pharmacist.

Inject this medication under the skin as directed by your doctor, usually once every week. The injection is given in the abdomen or thigh. Do not inject near the belly button or at the waistline. The dosage is based on your medical condition, lab tests, and response to treatment. Children's dosage is also based on body size.

For a more comfortable injection, take the medication out of the refrigerator and let it warm to room temperature as directed in the Instructions for Use. Do not warm up this medication any other way (for example, do not heat it in the microwave or place it in hot water). Do not shake this medication. Before using, check this product for particles or discoloration. If either is present, do not use the liquid. Before injecting each dose, clean the skin you are going to inject into (the injection site) with rubbing alcohol. Change the injection site each time to lessen injury under the skin. To lessen bruising, do not rub the injection site after a shot. Learn how to store and discard medical supplies safely.

Use this medication regularly to get the most benefit from it. To help you remember, use it at about the same time on the same day each week.

Drink plenty of fluids while using this medication unless your doctor directs you otherwise.