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Overview: Inhaled acetylcysteine is used to improve breathing if you have certain lung problems. It thins mucus in your airways caused by lung diseases. Common side effects may include mouth sores, nausea, vomiting, or a runny nose. Rarely inhaled acetylcysteine can cause the muscles around the airways to tighten. Contact your health care provider right away if you have trouble breathing. Talk to your health care provider about all of your medical conditions before you start using inhaled acetylcysteine. 

Uses

What is inhaled acetylcysteine used for?

Inhaled acetylcysteine is commonly used to thin mucus in your airways caused by lung diseases such as cystic fibrosis, pneumonia, emphysema, and bronchitis. 

Inhaled acetylcysteine may also be used for other conditions as determined by your health care provider.

Acetylcysteine is also used to treat acetaminophen (Tylenol) overdose. See Acetylcysteine for more information.

How does inhaled acetylcysteine work (mechanism of action)?

Inhaled acetylcysteine helps break down the thick mucus in your lungs, making the mucus easier to cough up and clear from your airways. This can be helpful in severe lung diseases and infections.

How is inhaled acetylcysteine supplied (dosage forms)?

Dosage forms and strengths

  • 10% solution for inhalation
  • 20% solution for inhalation

How should I store inhaled acetylcysteine?

Before opening, inhaled acetylcysteine should be stored at room temperature, between 68 F and 77 F (20 C and 25 C). It can be exposed to temperatures between 59 F and 86 F (15 C and 30 C), for shorter periods of time, such as when transporting it. After opening, inhaled acetylcysteine should be stored in a refrigerator, between 36 F and 46 F (2 C and 8 C) for up to 96 hours (4 days).

Side Effects

What are the most common side effects of inhaled acetylcysteine?

The most common side effects of inhaled acetylcysteine are listed below. Tell your health care provider if you have any of these side effects that bother you.

  • Mouth sores
  • Nausea and vomiting
  • Fever and runny nose
  • Drowsiness
  • Unpleasantly wet or sweaty skin
  • Chest tightness

There may be other side effects of acetylcysteine that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of inhaled acetylcysteine?

While less common, the most serious side effects of inhaled acetylcysteine are described below, along with what to do if they happen.

Severe Allergic Reactions. Inhaled acetylcysteine can cause allergic reactions, which can be serious. Stop using acetylcysteine and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble in swallowing or throat tightness
  • Itching or skin rash
  • Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Breathing Problems. Inhaled acetylcysteine may cause the muscles around the airways to tighten (bronchospasm) instead of relaxing, which can be serious. Stop using inhaled acetylcysteine and contact your health care provider right away if you have trouble breathing.

Warnings & Precautions

Who should not use inhaled acetylcysteine?

Allergies to Ingredients. People who are allergic to any of the following should not use inhaled acetylcysteine.

  • Acetylcysteine
  • Mucomyst
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific inhaled acetylcysteine products they stock.

What should I know about inhaled acetylcysteine before using it?

Do not use inhaled acetylcysteine unless it has been prescribed to you by a health care provider. Use it as prescribed.

Do not share inhaled acetylcysteine with other people, even if they have the same condition as you. It may harm them.

Keep inhaled acetylcysteine out of the reach of children. As opened inhaled acetylcysteine must be kept in a refrigerator, take special precautions to keep it away from children who also use the refrigerator.

You may notice an unpleasant smell when you first use inhaled acetylcysteine. Your face may also feel sticky after using the medicine with a face mask. Wash your face with water to remove the stickiness.

What should I tell my health care provider before using inhaled acetylcysteine?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if inhaled acetylcysteine is right for you.

In particular, make sure that you discuss any of the following.

Asthma or Problems Coughing. Make sure that you discuss if you have asthma or any problems coughing. Inhaled acetylcysteine may rarely cause the muscles around your airways to tighten (bronchospasm) right after you use it.

Pregnancy. It is not known if or how inhaled acetylcysteine could affect pregnancy or harm a fetus. Tell your health care provider if you are pregnant or plan to become pregnant. Your health care provider will let you know if you should use inhaled acetylcysteine while you are pregnant or trying to get pregnant.

Breastfeeding. It is not known if inhaled acetylcysteine passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should use inhaled acetylcysteine while breastfeeding.

Interactions

Does inhaled acetylcysteine interact with foods or drinks?

There are no known interactions between inhaled acetylcysteine and foods or drinks.

It is unknown if drinking alcohol will affect inhaled acetylcysteine.

Does inhaled acetylcysteine interact with other medicines (drug interactions)?

There are no known interactions between inhaled acetylcysteine and other medicines. Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much inhaled acetylcysteine?

If you or someone else has used too much inhaled acetylcysteine, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of inhaled acetylcysteine?

If you miss a dose, use it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only use the next dose. Do not use double or extra doses.