Acetylcysteine (a-se-teel-SIS-teen ) is a mucolytic (medicine that destroys or dissolves mucus). It is usually given by inhalation but may be given in other ways in a hospital.

Acetylcysteine is used for certain lung conditions when increased amounts of mucus make breathing difficult. Acetylcysteine liquefies (thins) or dissolves mucus so that it may be coughed up. Sometimes the mucus may have to be removed by suction.

This medicine is available only with your doctor's prescription, in the following dosage form:

Inhalation

• Solution (U.S. and Canada)

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• Less common
  • Wheezing, tightness in chest, or difficulty in breathing (especially in asthma patients) 

  
   

• Rare
  • Skin rash or other irritation 

  
   

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• Less common
  • Clammy skin;  fever;  increase in amount of mucus in lungs;  irritation or soreness of mouth, throat, or lungs;  nausea or vomiting;  runny nose 

  
   

For patients using a face mask for inhalation of acetylcysteine:

• The mask may leave a stickiness on your face. This can be removed with water.

When you use acetylcysteine, you may notice that the medicine has an unpleasant odor at first. However, this smell will go away soon after you use the medicine.