Read the Medication Guide and Instructions for Use provided by your pharmacist before you start using peginterferon 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 every 14 days. The injection is given in the thigh, abdomen, or the back of the upper arm. Check the injection site 2 hours after injecting to see if there is any reaction at the injection site. Tell the doctor of any skin reactions that do not go away after a few days.

To reduce your risk of side effects, your doctor may direct you to start this medication at a low dose and gradually increase your dose. A starter pack with different doses of this medication may be used when starting this medication. Follow your doctor's instructions carefully.

Take the medication out of the refrigerator at least 30 minutes before you inject it to allow it to reach room temperature. Do not warm up this medication any other way (for example, place it in hot water). 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. Do not inject into skin that is irritated, bruised, scarred, or infected. 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 the same time and same day of the week.

You may need to take other medications to reduce common side effects such as fever and pain (such as acetaminophen, ibuprofen). Consult your doctor or pharmacist about how to use these medications safely with peginterferon.

Tell your doctor if your condition worsens.