Recommended Dosing of Inhaled N-Acetylcysteine for Mucus Clearance
For mucus clearance, the recommended dose of inhaled N-acetylcysteine is 3-5 mL of 20% solution or 6-10 mL of 10% solution administered via nebulization 3-4 times daily. 1
Dosing Guidelines Based on Administration Method
Standard Nebulization (Face Mask, Mouthpiece, or Tracheostomy)
- Primary recommendation: 3-5 mL of 20% solution or 6-10 mL of 10% solution 3-4 times daily 1
- Range: 1-10 mL of 20% solution or 2-20 mL of 10% solution every 2-6 hours 1
Direct Instillation
- 1-2 mL of 10% or 20% solution as frequently as every hour 1
- For tracheostomy care: 1-2 mL of 10-20% solution every 1-4 hours 1
Tent or Croupette Administration
- Individualized dosing based on equipment and patient needs
- Sufficient volume to maintain heavy mist for desired period 1
- May require up to 300 mL during a single treatment period 1
Preparation and Administration Considerations
Solution Preparation
- 20% solution may be diluted with:
- Sodium Chloride Inhalation Solution
- Sodium Chloride Injection
- Sterile Water for Injection
- Sterile Water for Inhalation
- 10% solution may be used undiluted 1
Equipment Compatibility
- Compatible materials: glass, plastic, aluminum, anodized aluminum, chromed metal, tantalum, sterling silver, stainless steel
- Incompatible materials: certain metals (especially iron and copper) and rubber 1
- Use compressed air or oxygen for nebulization (with caution in patients with severe respiratory disease and CO2 retention) 1
Clinical Considerations
Efficacy and Evidence
- N-acetylcysteine depolymerizes mucus by breaking disulfide bonds, potentially decreasing mucus viscosity and improving airway clearance 2
- Evidence for inhaled NAC in cystic fibrosis is insufficient to recommend for or against routine use 2
- In critical situations, nebulized NAC has been reported as a life-saving mucolytic for resistant mucus plugging 3
Safety Profile
- Generally well-tolerated with no significant increase in adverse events compared to placebo 4
- Can be administered with a bronchodilator to prevent bronchospasm in asthmatic patients 5
Storage of Opened Vials
- No antimicrobial agent in the solution
- If partially used, refrigerate remainder and use within 96 hours 1
Caution
- NAC may react with certain materials in nebulization equipment, particularly metals and rubber 1
- When used in asthmatic patients, consider co-administration with a bronchodilator to prevent bronchospasm 5
While the Cystic Fibrosis Foundation concluded that evidence is insufficient to recommend routine use of inhaled NAC 2, the FDA-approved dosing provides clear guidance for when it is clinically indicated for mucus clearance.