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N-A-C Sustain

Generic Name: Acetylcysteine (oral) [ a-SEET-ilSIS-teen].

Brand Names: NAC, N-A.C. Sustain.

What is N-A-C Sustain?

N-A-C Sustain is used to aid in preventing or reducing the damage to the liver caused by the consumption of large amounts of acetaminophen (Tylenol). There are different types and brands of acetylcysteine available, and some are bought over the counter. There are a few forms of N-A-C Sustain that work as an antidote for acetaminophen. Don't try to treat an overdose of acetaminophen without a medical diagnosis. N-A-C Sustain can be used for other purposes not covered in this medication guide.

Side effects of N-A-C sustains

Contact a medical professional immediately. Get medical attention immediately if you notice symptoms that are warning signs of an allergic response, such as difficulty breathing, hives, or swelling of your lips, face, or tongue.

N-A-C Sustain could cause serious adverse side effects. Consult your physician right away if you experience:

  • Severe or ongoing vomiting.
  • Vomiting blood or vomit that resembles coffee grounds.
  • Symptoms that indicate the medicine might not be effective: stomach pain, a loss of appetite, dark urine, black or white stool, and jaundice (yellowing of the eyes or skin).

Common adverse effects of NAC Sustain could be:

  • Nausea, vomiting, upset stomach.
  • Fever.
  • Rashes.

This is not a comprehensive list of all the side effects. Others could happen. Consult your physician for advice regarding medical adverse effects. You can report any adverse reactions to the FDA at 1-800-FDA-1088.


In the event of an emergency, there is a chance that you will not be able to inform your caregivers about any health issues. Be sure that any physician caring for you afterwards knows you've received N-A-C-Maintenance.

Before you take this drug

It is recommended not to use N-A-C Sustain if you have an allergy to it. If you are able to, before you receive N-A-C Sustain, inform your medical professionals if you've previously had:

  • A stomach ulcer.
  • The stomach is bleeding, or it is inside your esophagus (esophageal varices).
  • High blood pressure in the event that you're on an e-diet that is low in salt.
  • Congestive heartfailure.
  • Kidney disease.

Talk to your doctor before taking this medication if you are breastfeeding or pregnant. In an emergency situation, you might not be able to tell your caregivers that you are breastfeeding or pregnant. It is important that the doctor who is caring for the baby or your pregnancy is aware that you have received this medication.

What should be avoided?

Follow the instructions on the label exactly or as recommended by your physician.

Do not consume NAC. Take it home if you aren't able to follow all the instructions.

If you're in a medical emergency, Prior to taking N-A-C Sustain, your medical professional will conduct tests on your blood to assess the level of acetaminophen within your body. The test is most efficient when done within 4–8 hours following an overdose of acetaminophen. If you are unable to remember the last time you consumed acetaminophen or the amount you consumed, you will most likely receive an initial dose of acetylcysteine right from the beginning. Your doctor will decide how long you should be treated with N-A-C Sustain. Don't stop taking NAC Sustain until your doctor instructs you to. If you have diarrhea within 1 hour of taking N-A-C Sustain, it is possible to take a different dose. Keep at room temperature, free of heat and moisture.

What happens if I miss a dose?

You should take the medication as quickly as you can. However, avoid your missed dose if you are nearing the time to take the next dose. Don't take two doses at a time.

What happens if I overdose?

Get medical attention in an emergency or contact the poison help line at 1-800-222-1222.

What should be avoided?

Follow the instructions of your physician regarding any limitations on foods, drinks, or any activity.

Interaction with other drugs

Other medications may interact with N-A-C Sustain's effects, such as medications that are prescribed and available over the counter, vitamins, and herbal products. Discuss with your doctor your current medications as well as any medications you are about to start or stop taking.