What are the uses of N-acetylcysteine (NAC) inhalation?

From the Guidelines

N-acetylcysteine (NAC) inhalation is not the primary method of administration for treating respiratory conditions, as the provided evidence suggests oral administration is more commonly studied and recommended. The use of NAC in respiratory conditions is primarily focused on its mucolytic properties, which help thin and loosen mucus in the airways, making it easier to cough up secretions and improve breathing 1.

Key Points

• NAC is used to treat respiratory conditions such as chronic bronchitis and COPD by reducing the viscosity of respiratory secretions 1.
• The evidence provided focuses on oral NAC administration, with studies showing a reduction in the rate of exacerbations in COPD patients compared to placebo 1.
• Oral NAC has been shown to be well-tolerated, with no significant difference in adverse events compared to placebo 1.
• The typical dosage of oral NAC is 600 mg once or twice daily, as seen in the studies by Pela et al and Zheng et al 1.

Administration and Side Effects

When using NAC, patients may experience side effects such as throat irritation, nausea, or bronchospasm, although these are more commonly associated with inhalation administration 1. It is essential to use the medication as directed and follow proper storage and handling instructions. Patients with asthma should use NAC cautiously, as it may trigger bronchospasm in some cases.

Evidence-Based Recommendation

Based on the most recent and highest quality evidence, oral NAC administration is recommended for patients with COPD and chronic bronchitis to reduce the rate of exacerbations 1. The evidence suggests that oral NAC is well-tolerated and effective in reducing exacerbations, with a significant reduction in the rate of hospitalizations due to COPD exacerbations 1.

From the FDA Drug Label

Acetylcysteine is indicated as adjuvant therapy for patients with abnormal, viscid, or inspissated mucous secretions in such conditions as: Chronic bronchopulmonary disease (chronic emphysema, emphysema with bronchitis, chronic asthmatic bronchitis, tuberculosis, bronchiectasis and primary amyloidosis of the lung) Acute bronchopulmonary disease (pneumonia, bronchitis, tracheobronchitis) Pulmonary complications of cystic fibrosis Tracheostomy care Pulmonary complications associated with surgery Use during anesthesia Post-traumatic chest conditions Atelectasis due to mucous obstruction Diagnostic bronchial studies (bronchograms, bronchospirometry, and bronchial wedge catheterization)

The uses of N-acetylcysteine inhalation include:

• Mucolytic therapy for patients with abnormal, viscid, or inspissated mucous secretions
• Treatment of chronic bronchopulmonary disease, such as chronic emphysema and bronchiectasis
• Treatment of acute bronchopulmonary disease, such as pneumonia and bronchitis
• Management of pulmonary complications of cystic fibrosis
• Tracheostomy care and post-traumatic chest conditions
• Use during anesthesia and pulmonary complications associated with surgery 2

From the Research

Uses of NAC Inhalation

• NAC inhalation is used for its mucolytic effects in the treatment of chronic respiratory diseases, including cystic fibrosis 3.
• It is also used as an antidote in acetaminophen (paracetamol) overdosing 3.
• NAC has antioxidative and anti-inflammatory effects, making it potentially beneficial for other chronic inflammatory and fibrotizing respiratory diseases, such as:
  • Chronic obstructive pulmonary disease (COPD) 3, 4, 5, 6
  • Bronchial asthma 3
  • Idiopathic lung fibrosis 3
  • Lung silicosis 3
• NAC may be useful as an adjuvant in treating various medical conditions, including:
  • Polycystic ovary disease 4
  • Male infertility 4
  • Sleep apnea 4
  • Acquired immune deficiency syndrome 4
  • Influenza 4
  • Parkinsonism 4
  • Multiple sclerosis 4
  • Peripheral neuropathy 4
  • Stroke outcomes 4
  • Diabetic neuropathy 4
  • Crohn's disease 4
  • Ulcerative colitis 4
  • Schizophrenia 4
  • Bipolar illness 4
  • Obsessive compulsive disorder 4
• NAC can also be used as a chelator for heavy metals and nanoparticles 4.

Dosage and Efficacy

• The efficacy of NAC in preventing exacerbations of chronic bronchitis or COPD has been demonstrated in several studies, with a significant reduction in the incidence of exacerbations compared to placebo 5, 6, 7.
• The optimal dosage of NAC for chronic bronchitis or COPD is still unclear, but studies suggest that a regular treatment of 600-1200 mg per day may be effective 5, 7.
• NAC has been shown to improve symptoms and quality of life in patients with chronic bronchitis or COPD, in addition to preventing exacerbations 6, 7.