NAC stands for N-acetyl L-cysteine. NAC is a modified version of the amino acid acetylcysteine. Doctors primarily use acetylcysteine injections to treat acetaminophen overdose, or they use it in nebulized or oral form to treat lung conditions. However, most people are familiar with NAC dietary supplements.
Check our best N-Acetylcysteine prices
N-Acetylcysteine overview
BRAND NAMES:
NACsentials, N-A-C Sustain, Neuro-NAC, The NAC Gummy, Ultra NAC
Generic Names:
N-acetyl-L-cysteine
Uses:
Helps prevent liver damage caused by an overdose of acetaminophen, loosens mucus in the lungs, and is taken as a supplement for various health benefits.
Therapeutic Classes:
Acetaminophen antidote, mucolytic, amino acid supplement, antioxidant, anti-inflammatory
Forms:
Liquid, capsule, tablet, effervescent tablet, powder, gummy
How it’s taken:
Injection, nebulized, by mouth
What is N-Acetylcysteine used for?
Healthcare professionals use NAC injections to treat acetaminophen overdoses. They also use NAC solution in nebulizers to loosen mucus in people with serious lung conditions, including COPD, bronchitis, tuberculosis, amyloidosis, cystic fibrosis, tracheostomy, surgery, trauma, lung collapse, and other conditions. Healthcare professionals may also use oral doses of NAC for some lung issues. Over-the-counter NAC supplements are taken for various health benefits. Off-label uses of oral NAC include preventing kidney damage from contrast dyes, reducing the incidence and severity of flu infections, loosening lung mucus in people with cystic fibrosis, or treating polycystic ovarian syndrome (PCOS).
What form(s) does N-Acetylcysteine come in?
Solution for injection (Rx)
200 mg/mL (requires dilution before injection)
Solution for nebulization (Rx)
10% (100 mg/mL)
20% (200 mg/mL)
Capsule (OTC)
500 mg
600 mg
900 mg
1,000 mg
1,200 mg
1,300 mg
1,600 mg
1,800 mg
Tablets (OTC)
600 mg
1,000 mg
Effervescent tablet (OTC)
600 mg
Powder (OTC)
600 mg/serving
Gummies (OTC)
300 mg
600 mg
What are common N-Acetylcysteine dosages?
For acetaminophen poisoning: Intravenous infusion administered by healthcare professionals
For loosening mucus due to lung conditions, trauma, or tracheostomy:
By nebulizer face mask or mouthpiece: 1–10 mL of 20% solution or 2–20 mL of 10% solution administered every 2–6 hours, usually by a healthcare professional
By nebulizer tent or croupette: Variable amounts (as high as 300 mL of 20% solution) for intermittent or continuous periods administered by healthcare professionals
By direct installation through a catheter: 1–2 mL of 10% or 20% solution as often as once per hour administered by a healthcare professional
Oral NAC: 600 mg/day
Oral NAC prescribed:
To prevent COPD exacerbations: 1,800 mg per day taken in divided doses
For PCOS: 1,200 mg per day taken in divided doses
For idiopathic cystic fibrosis: 600 mg three times per day
As a dietary supplement: 600–1,800 mg/day, depending on the product labeling
As a dietary supplement to attenuate flu: 600 mg twice per day
N-Acetylcysteine images - What does N-Acetylcysteine look like?
NAC
100 capsules bottle
How to take N-Acetylcysteine
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.
What to do if you miss a dose of N-Acetylcysteine
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.
N-Acetylcysteine contraindications - Who shouldn't take N-Acetylcysteine?
Do not take NAC supplements if you are allergic to acetylcysteine or any of the product's ingredients or preservatives.
N-Acetylcysteine warnings
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.
N-Acetylcysteine interactions & what to avoid when taking N-Acetylcysteine
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.
N-Acetylcysteine side effects - How does N-Acetylcysteine make you feel?
Serious side effects
Talk to a doctor if you notice any signs or symptoms of a possible serious side effect, including:
Severe or ongoing vomiting
Blood or blood clots in the vomit, dark and tarry stools
Allergic reaction: Rash, hives, headache, ringing in the ears, chills, fever, lightheadedness, trouble breathing, chest tightness
Less serious side effects
Nausea
Vomiting
Diarrhea
Gas
Mouth sores or swelling (inhaled NAC)
Runny nose (inhaled NAC)
Drowsiness (inhaled NAC)
Vomiting (NAC injections)
Flushing or hives (NAC injections)
Sources:
Acetylcysteine (inhalation), Wheatfield Pediatrics
Acetylcysteine (inhalation route), Mayo Clinic
Acetylcysteine inhalation solution, Cleveland Clinic
Acetylcysteine injection, DailyMed (NIH National Library of Medicine)
Acetylcysteine solution, DailyMed (NIH National Library of Medicine)
Attenuation of influenza-like symptomatology and improvement of cell-mediated immunity with long-term N-acetylcysteine treatment, The European Respiratory Journal
Cysteine information, Mount Sinai
N-acetylcysteine, StatPearls
N-acetylcysteine: A rapid review of the evidence for effectiveness in treating COVID-19, The Centre for Evidence-Based Medicine
N-acetylcysteine for polycystic ovary syndrome: A systematic analysis of randomized controlled clinical trials, Obstetrics and Gynecology International
N-acetylcysteine: multiple clinical applications, American Family Physician
Subscribe to our savings newsletter
Health education, drug info, wellness & more
By clicking 'Subscribe', I agree to SingleCare's Terms & Conditions.
