If you experience any of the following serious side effects while taking dornase alfa, seek emergency medical attention or contact your doctor immediately:

• an allergic reaction (difficulty breathing; closing of the throat; swelling of the lips, tongue, or face; or hives);
• increased difficulty breathing;
• chest pain
• fever.

Less serious side effects may be more likely to occur with the use of dornase alfa. Talk to your doctor if you experience any of the following side effects:

• voice alteration;
• sore throat;
• rash;
• laryngitis;
• eye redness, irritation, or inflammation; 
• nasal stuffiness or discharge;
• cough

 Dornase alfa is a man-made protein similar to a natural protein in your body called DNase.  It works by helping to break down the thick mucus produced in the lungs of patients with cystic fibrosis.

• Do not use if allergic to dornase alfa or to any of the other ingredients in this product.
• Before using dornase alfa, tell your doctor if you have any other medical conditions or if you take other prescription or over-the-counter medicines. You may require a dosage adjustment or special monitoring during your treatment.

Drug interactions:

• no known drug interactions

Safety in pregnancy: There is no human data on use in pregnancy however, dornase alfa is not expected to be harmful to an unborn baby. Do not use this medication without first talking to your doctor if you are pregnant or could become pregnant during treatment.

Safety in breastfeeding: It is not known whether dornase alfa passes into breast milk, however use is not expected to be harmful to the baby.  Do not use dornase alfa without first talking to your doctor if you are breastfeeding.