What is the daily dose of N-Acetylcysteine (NAC)?

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Last updated: February 4, 2025View editorial policy

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From the Guidelines

The daily dose of N-Acetylcysteine (NAC) is 200-500 mg/day for patients with chronic oxidative stress or malabsorption, as recommended by the espen micronutrient guideline 1.

Key Points

  • The recommended dose range is based on a strong consensus of 92% in the guideline.
  • This dose range is applicable for patients with conditions such as diabetes mellitus, smoking, heart failure, alcoholism, severe COPD, and chronic dialysis.
  • The evidence from other studies, such as those on IPF 1, COPD 1, and idiopathic pulmonary fibrosis 1, does not provide a clear consensus on the daily dose of NAC, but the dose range of 200-500 mg/day is generally considered safe and effective.
  • In specific cases, such as acetaminophen overdose, the dose of NAC may be higher, up to 140 mg/kg orally or intravenously, as recommended by the AASLD position paper 1.

Important Considerations

  • The dose of NAC may vary depending on the specific condition being treated and the individual patient's needs.
  • NAC is generally well-tolerated, but may cause side effects such as nausea, vomiting, and rare allergic reactions.
  • The evidence for the use of NAC in certain conditions, such as IPF, is still limited and inconclusive, and further research is needed to determine its effectiveness.

From the FDA Drug Label

DOSAGE GUIDE AND PREPARATION Doses in relation to body weight are: Loading Dose of Acetylcysteine ** ... Maintenance Dose** (kg) (lb) ... **If patient weighs less than 20 kg (usually patients younger than 6 years), calculate the dose of acetylcysteine. The loading dose is 140 mg per kilogram of body weight. The maintenance dose is 70 mg/kg.

The daily dose of N-Acetylcysteine (NAC) is not explicitly stated as a single value, but rather as a loading dose of 140 mg/kg and a maintenance dose of 70 mg/kg, with the total daily dose depending on the patient's weight.

  • For patients over 20 kg, the total daily dose can be calculated based on the provided tables.
  • For patients under 20 kg, the dose is calculated as 140 mg/kg for the loading dose and 70 mg/kg for the maintenance dose 2.

From the Research

Daily Dose of N-Acetylcysteine (NAC)

The daily dose of N-Acetylcysteine (NAC) varies depending on the condition being treated.

  • For chronic respiratory diseases, the maximum licensed dose is 600 mg/day 3.
  • However, some studies have used higher doses, up to 3000 mg/day, with a similar safety profile to the standard dose 3.
  • A study on patients with chronic obstructive pulmonary disease (COPD) found that a dose of 1200 mg/day was optimal, both clinically and in terms of antioxidant activity 4.
  • Another study on COPD patients found that high-dose NAC (1200 mg/day) was more efficacious than a lower dose (600 mg/day) in reducing inflammatory markers and improving clinical outcomes 5.
  • For the treatment of early-stage COPD, a randomized controlled trial is investigating the efficacy and safety of NAC 600 mg twice daily 6.
  • In cases of massive acetaminophen overdose, a step-wise increase in NAC dosing may be beneficial, with proposed doses at the 300-, 450-, and 600-lines 7.

Key Findings

  • The safety profile of NAC is similar at both high and standard doses 3.
  • High-dose NAC may be more efficacious than lower doses in reducing inflammatory markers and improving clinical outcomes in COPD patients 4, 5.
  • The optimal dose of NAC for COPD patients may be 1200 mg/day 4, 5.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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