This medication is used to improve breathing and reduce the risk of lung infections in people with cystic fibrosis. It is used along with other treatments for this disease (such as chest physical therapy, medications, nutritional supplements). Dornase alfa is the same as a substance (DNase I enzyme) that is naturally produced by the body. It works in the airways by decreasing stickiness/thickness of mucus so that it can be cleared from the lungs more easily.

Read the Instructions for Use if available from your pharmacist before you start using dornase alfa and each time you get a refill. If you have any questions, ask your doctor or pharmacist.

This medication is inhaled into the lungs using special breathing equipment as directed by your doctor, usually once or twice daily. A health care professional will show you the proper way to prepare the medication and use the equipment. If you are unclear about any of the instructions, ask your health care professional.

The dosage is based on your medical condition and response to treatment. Do not increase your dose or take this medication more often than prescribed. Your condition will not improve faster and the risk for side effects may be increased.

Use this medication regularly to get the most benefit from it. To help you remember, use it at the same time(s) each day.

Sore/dry throat and hoarseness may occur. Eye redness/irritation may also rarely occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including:

• chest pain

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• unusual trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before using dornase alfa, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history.

Tell your doctor if you are pregnant before using this medication.

It is unknown if this medication passes into breast milk. Consult your doctor before breastfeeding.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Do not share this medication with others.

If you miss a dose, use it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Use your next dose at the regular time. Do not double the dose to catch up.

Store in the refrigerator away from light and heat. Do not freeze. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.