Acetylcysteine Effervescent Tablet Uses
Acetylcysteine effervescent tablets are primarily indicated for preventing acute exacerbations in patients with moderate-to-severe COPD who continue to have recurrent exacerbations despite optimal inhaled therapy, and as an antidote for acetaminophen overdose. 1
FDA-Approved Indications
Acetylcysteine is FDA-approved as adjuvant therapy for patients with abnormal, viscid, or inspissated mucous secretions in the following conditions: 2
- Chronic bronchopulmonary disease (chronic emphysema, emphysema with bronchitis, chronic asthmatic bronchitis, tuberculosis, bronchiectasis, and primary amyloidosis of the lung) 2
- Acute bronchopulmonary disease (pneumonia, bronchitis, tracheobronchitis) 2
- Pulmonary complications of cystic fibrosis 2
- Tracheostomy care and post-traumatic chest conditions 2
- Acetaminophen overdose as an antidote to prevent or lessen hepatic injury 2
Evidence-Based Clinical Uses
COPD Exacerbation Prevention (Primary Indication)
For patients with moderate-to-severe COPD and a history of two or more exacerbations in the previous 2 years, oral N-acetylcysteine 600 mg twice daily is recommended to prevent acute exacerbations (Grade 2B). 1
- This recommendation applies specifically to patients already on maintenance bronchodilator therapy and inhaled corticosteroids who continue to have periodic exacerbations 1
- NAC reduces exacerbation rates by approximately 22% (1.16 vs 1.49 exacerbations, RR 0.78) 3
- The drug appears more effective in moderate COPD (GOLD II) compared to severe disease (GOLD III) 3
- NAC has a low risk of adverse effects, primarily mild gastrointestinal symptoms 1
Acute Liver Failure
NAC significantly improves outcomes in acute liver failure from any cause, not just acetaminophen poisoning. 1
- Transplant-free survival: 64% vs 26% (OR 4.81,95% CI 3.22-7.18) 1, 3
- Overall survival: 76% vs 59% (OR 2.30,95% CI 1.54-3.45) 1, 3
- Post-transplant survival: 85.7% vs 71.4% (OR 2.44,95% CI 1.11-5.37) 1, 3
- Treatment should be started as early as possible, with benefits confined to patients with grades I-II coma 1
Acetaminophen Overdose
NAC is the drug of choice for acetaminophen poisoning, reducing hepatotoxicity (18% vs 58%, RR 0.31) and mortality (0.7% vs 6%, RR 0.12). 1
- Must be initiated within 24 hours of ingestion, with maximum benefit when started within 16 hours 2
- Loading dose: 140 mg/kg orally, followed by maintenance doses of 70 mg/kg every 4 hours 2
Important Clinical Caveats
NOT Effective for Cough Treatment
Acetylcysteine is inactive against cough in patients with chronic bronchitis, and should NOT be used for symptomatic cough relief. 4, 5
- Cough frequency and intensity may be independent of mucus properties in chronic bronchitis 4
- For cough relief, codeine or dextromethorphan are recommended instead (Grade B) 5
- Ipratropium bromide is preferred for improving cough in stable chronic bronchitis (Grade A) 4
Limited Evidence in Cystic Fibrosis
Evidence is insufficient to recommend for or against routine chronic use of inhaled N-acetylcysteine in cystic fibrosis (Grade I - insufficient evidence). 4, 3
- Dornase alfa is the only mucolytic with proven efficacy in cystic fibrosis 4
Safety Considerations
- Adverse effects are primarily gastrointestinal (nausea, vomiting, diarrhea), with rare skin rash (<5%) or transient bronchospasm (1-2%) 1, 3
- Inhaled NAC may cause bronchoconstriction, particularly in patients with reactive airways 4
- NAC has low toxicity even with prolonged use and when combined with other treatments 3, 6
Dosing for Chronic Use
Standard dose for COPD exacerbation prevention: 600 mg orally twice daily, with no specific dose adjustment required for age alone. 3
- This is for ongoing chronic use in appropriate patients 3
- Renal function should be monitored during prolonged therapy 3