What is N-Acetylcysteine: Uses, Warnings & Interactions

Acetylcysteine for acetaminophen overdose:

• Healthcare professionals administer acetylcysteine injections in a monitored setting.

• Acetylcysteine works best at protecting the liver from damage the soonest it’s administered, so get immediate emergency medical help if an acetaminophen overdose is suspected.

• After eight hours following an acetaminophen overdose, the acetylcysteine injection will not be as effective.

• After release from the hospital, oral doses of acetylcysteine may be required. These doses are usually taken as an oral solution, which requires dilution before administration. Take all doses as prescribed. Do not stop taking NAC until instructed by the doctor.

How to use acetylcysteine for lung conditions:

• A healthcare professional will administer acetylcysteine solution for lung conditions or self-administer it at home with a nebulizer.

• For use at home, a healthcare professional will train patients or caregivers to use acetylcysteine solution and administer doses. Understand and follow these directions.

• Follow all the dosing directions given by the doctor or printed on the prescription label.

• Use only the inhaler provided with the medicine.

• If the solution requires dilution, use the diluted mixture within 90 minutes of mixing it. Do not dilute the solution until ready to give a dose.

• Never place the acetylcysteine solution directly in a heated nebulizer chamber.

• After the dose is finished, try to cough up mucus.

• Clean the nebulizing equipment immediately after use.

• Store the unopened bottle at room temperature.

• If any solution remains in an open bottle, store it in the refrigerator in a tightly closed bottle. Do not freeze. Throw it out after 96 hours (four days).

How to take NAC capsules or tablets:

• Use only the amount prescribed by the doctor. Do not exceed the dose.

• If using over-the-counter NAC tablets, do not exceed the recommended dosage printed on the package.

• Swallow NAC tablets or capsules whole with a drink of water.

• Store NAC tablets and capsules at room temperature, protected from heat and moisture.

How to take NAC effervescent tablets:

• Dissolve the effervescent tablets in water and drink the mixture within 2 hours.

• Store NAC effervescent tablets at room temperature, protected from heat and moisture.

How to use NAC powder:

• Follow the package directions. These instructions will vary between products.

• Store NAC powder at room temperature, protected from heat and moisture.

Talk to the doctor about what to do if a dose is missed for inhaled NAC.

For oral NAC, take a missed dose as soon as you remember.

• If you vomit within 1 hour after you take a NAC dose, take another dose to make up for it.

Do not take NAC supplements if you are allergic to acetylcysteine or any of the product's ingredients or preservatives.

Tell any doctor or other healthcare provider who treats you that you are using this medicine.

If you are using NAC for inhalation, the doctor will schedule regular appointments to check the effects of this medicine and perform blood tests. Keep all appointments.

If you are taking NAC for inhalation or being treated for acetaminophen overdose, tell the doctor if you have:

• Lung blockage (if using inhaled NAC)

• Asthma

• Stomach ulcers

• Bleeding in the esophagus

• A kidney disorder called cystinuria

• Had an allergic reaction to acetylcysteine or preservatives in medicines

Tell your doctor if you are pregnant or breastfeeding.

This medicine may increase the risk of bleeding in your esophagus and stomach.

Never give NAC to a child unless told to do so by a doctor.

If you are taking NAC supplements, consider talking to a doctor first. Side effects are minimal at low dosages (less than 1,200 mg per day), but high doses may cause problems. 

To avoid potentially hazardous drug interactions, tell the prescribing healthcare provider about all prescription drugs, over-the-counter medicines, and supplements before using NAC, particularly:

• The angina treatment nitroglycerin

• The anti-seizure medication carbamazepine

Tell other healthcare providers you are using this medicine before they prescribe new medications.