Acetyl%25252525252525252525252525252525252525252525252525252525252525252520cysteine

# Acetylcysteine ## Overview Acetylcysteine (N-acetylcysteine, NAC) is a mucolytic agent and an antidote for acetaminophen overdose. It works by replenishing glutathione stores and directly acting as a mucolytic. ## Primary Indications * **Acetaminophen Overdose:** To prevent or reduce liver toxicity. * **Mucolytic:** To thin and loosen mucus in patients with acute bronchitis, chronic bronchitis, emphysema, cystic fibrosis, and pneumonia. ## Adult Dosing * **Acetaminophen Overdose Management (Oral Protocol):** * Loading Dose: 140 mg/kg as a single dose. * Maintenance Dose: 70 mg/kg every 4 hours for 17 additional doses (17 doses total including loading dose). * Maximum initial dose: 140 mg/kg. * **Acetaminophen Overdose Management (Intravenous Protocol):** * Specific dosing protocols vary (e.g., 150 mg/kg IV over 60 minutes, then 12.5 mg/kg/hour IV for 4 hours, then 6.25 mg/kg/hour IV for 16 hours). **Consult local protocol.** * **Mucolytic (Nebulization):** 1-2 mL of 20% solution or 2-4 mL of 10% solution every 2-6 hours as needed. ## Pediatric Dosing * **Acetaminophen Overdose Management (Oral Protocol):** * Loading Dose: 140 mg/kg as a single dose. * Maintenance Dose: 70 mg/kg every 4 hours for 17 additional doses. * Maximum initial dose: 140 mg/kg. * **Acetaminophen Overdose Management (Intravenous Protocol):** * Dosing is weight-based, similar to adults. **Consult local protocol.** * **Mucolytic (Nebulization):** * 0-1 month: 1 mL of 20% solution or 2 mL of 10% solution every 2-6 hours. * >1 month: 1-2 mL of 20% solution or 2-4 mL of 10% solution every 2-6 hours. ## Dose Adjustments No specific dose adjustments are typically required for hepatic or renal impairment for the antidote indication, although caution is advised due to potential for toxicity. ## Contraindications * Hypersensitivity to acetylcysteine or other components. * Certain patients with asthma may have increased risk of bronchospasm with nebulized acetylcysteine. ## Adverse Effects * **General:** Nausea, vomiting, rash, pruritus, fever, chills. * **Nebulized:** Bronchospasm, stomatitis, rhinorrhea. * **Intravenous:** Anaphylactoid reactions (flushing, rash, urticaria, angioedema, bronchospasm, hypotension), thoracic pain, fever. ## Key Drug Interactions * **Activated Charcoal:** Decreases absorption of oral acetylcysteine. If both are used, administer charcoal at least 1 hour after acetylcysteine. * **Nitroglycerin:** May potentiate hypotensive effects. ## Monitoring * **For Acetaminophen Overdose:** Liver function tests (ALT, AST, bilirubin, INR), creatinine, electrolytes, glucose, acetaminophen levels. * **For Mucolytic Use:** Respiratory status, presence of bronchospasm. ## Clinical Pearls * The oral antidote protocol for acetaminophen overdose is generally preferred when oral administration is feasible and vomiting is not severe. * Intravenous acetylcysteine is associated with a higher incidence of anaphylactoid reactions compared to oral administration. Pre-treatment with antihistamines and/or bronchodilators may be considered. * Nebulized acetylcysteine has an unpleasant odor. * Ensure adequate hydration when using acetylcysteine as a mucolytic. *Disclaimer: This information is intended for healthcare professionals. Always consult the most current prescribing information and local protocols for definitive guidance.*