When inhaled by mouth, acetylcysteine is used to help thin and loosen mucus in the airways due to certain lung diseases (such as emphysema, bronchitis, cystic fibrosis, pneumonia). This effect helps you to clear the mucus from your lungs so that you can breathe easier.

When taken by mouth, acetylcysteine is used to prevent liver damage from acetaminophen overdose.

This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.

.This drug may also be taken by mouth to reduce the risk of kidney damage due to dyes from certain X-ray procedures (such as CT scan).

If you are using this medication to treat lung disease, inhale this medication by mouth as directed by your doctor. A health care professional will show you the proper way to use this medication. Learn all preparation and usage instructions.

You may notice a slight odor when you first breathe in the medication. This odor will quickly go away. If you are using a face mask to breathe in the medication, there may be some stickiness on your face after use. Wash your face with water to remove the stickiness.

Do not mix acetylcysteine with other inhaled medications unless directed by the doctor or pharmacist.

If you are taking this medication by mouth, take it as directed by your doctor. The solution is usually mixed with another liquid (such as cola) to decrease nausea and vomiting. Drink the medication within 1 hour of mixing.

Tell your doctor if you vomit within 1 hour after taking your medication. You may need to take another dose.

The dosage is based on your medical condition and response to treatment. For acetaminophen overdose, the dosage is also be based on your weight.

Tell your doctor if your condition does not get better or if it gets worse.

Nausea and vomiting may occur. Mouth sores and runny nose may also occur if you are inhaling this medication by mouth. 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.

If you are taking this medication by mouth, tell your doctor right away if you have any serious side effects, including:

• severe stomach/abdominal pain
• black stools
• vomit that looks like coffee grounds

If you are inhaling this medication by mouth, get medical help right away if you have any very serious side effects, including:

• chest pain/tightness
• trouble breathing

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
• 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 acetylcysteine, 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, especially of:

• asthma
• stomach/intestinal ulcer

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

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

See also How to Use section.

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.

This medication may interfere with certain lab tests (such as urine ketone test), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.

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.

For acetaminophen overdose, lab and/or medical tests (such as liver/kidney function, acetaminophen drug levels, blood mineral levels) should be done while you are using this medication. Keep all medical and lab appointments. Consult your doctor for more details.

If you are using this medication to treat lung disease and 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.

If you are using this medication to treat acetaminophen overdose, it is important to take each dose as scheduled. If you miss a dose, ask your doctor or pharmacist right away for a new dosing schedule.

Store at room temperature away from light. Do not store in the bathroom. After opening the vial, store this medication in the refrigerator. Opened vials expire after 4 days. The solution may change to a light purple color. This is normal and will not affect how the drug works. 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.