NAC Uses, Side Effects & Warnings - Drugs.com

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# NAC

Generic name: acetylcysteine (oral) [ a-SEET-il-SIS-teen ]
Brand names: NAC, N-A-C Sustain

Medically reviewed by Drugs.com on Dec 26, 2022. Written by Cerner Multum.

## What is NAC?

NAC is used to help prevent or lessen liver damage caused by taking large quantities of acetaminophen (Tylenol).

There are other brands and forms of acetylcysteine available, and some can be purchased over the counter. Not all forms of NAC are effective as an acetaminophen antidote. Do not attempt to treat an acetaminophen overdose without medical advice.

NAC may also be used for purposes not listed in this medication guide.

## Warnings

In an emergency, you may not be able to tell caregivers about your health conditions. Make sure any doctor caring for you afterward knows you received this medicine.

## Before taking this medicine

You should not use NAC if you are allergic to it.

If possible before you receive NAC, tell your caregivers if you have ever had:

- a stomach ulcer;

- stomach bleeding or bleeding in your esophagus (esophageal varices);

- high blood pressure, or if you are on a low-salt diet;

- congestive heart failure; or

- kidney disease.

Ask a doctor before using NAC if you are pregnant or breastfeeding.

In an emergency, you may not be able to tell caregivers if you are pregnant or breast feeding. Make sure any doctor caring for your pregnancy or your baby knows you received this medicine.

## How should I take NAC?

Use exactly as directed on the label, or as prescribed by your doctor.

Do not take NAC at home if you don't understand all instructions.

If you are in an emergency medical setting: Before you take NAC, your caregivers will perform a blood test to measure the level of acetaminophen in your body. This test is most effective when performed within 4 to 8 hours after an acetaminophen overdose. If you cannot remember when you last took acetaminophen or how much you took, you will most likely be given the first dose of acetylcysteine right away.

Your doctor will determine how long to treat you with NAC. Do not stop taking this medicine until your doctor tells you to.

If you vomit within 1 hour after taking NAC, you may need to take another dose.

Store at room temperature away from moisture and heat.

Detailed NAC dosage information

## What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

## What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

## What should I avoid while taking NAC?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

## NAC side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

NAC may cause serious side effects. Call your doctor at once if you have:

- severe or ongoing vomiting;

- coughing up blood or vomit that looks like coffee grounds; or

- signs that the medicine may not be working--upper stomach pain, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Common side effects of NAC may include:

- nausea, vomiting, upset stomach;

- rash; or

- fever.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

NAC side effects (more detail)

## What other drugs will affect NAC?

Other drugs may affect NAC, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

NAC drug interactions (more detail)

## Where can I get more information?

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

## Popular FAQ

What is Fluimucil used for?

Fluimucil is a brand name for acetylcysteine sachets and tablets which may be used to clear phlegm and liquefy thick and viscous mucus secretions caused by respiratory conditions such as acute bronchitis, chronic bronchitis, cystic fibrosis, pneumonia, pulmonary emphysema, or bronchiectasis. It is a type of mucolytic. Fluimucil is available over the counter (without a prescription) in most countries that have it. Continue reading

## More about NAC (acetylcysteine)

- Check interactions
- Reviews (5)
- Side effects
- Dosage information
- During pregnancy or Breastfeeding
- En español

### Patient resources

#### Other brands

Mucomyst, N-A-C Sustain, Acetadote, Cetylev, Acys-5

### Professional resources

- Prescribing Information

### Related treatment guides

- Dietary Supplementation

## Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

Copyright 1996-2023 Cerner Multum, Inc. Version: 3.01.