Acetyl%25252525252525252525252525252520cysteine

# Acetylcysteine ## Overview Acetylcysteine (N-acetyl-L-cysteine) is a mucolytic agent and, crucially, a precursor to glutathione used as a specific antidote for acetaminophen (APAP) toxicity. It restores hepatic glutathione stores to neutralize the toxic NAPQI metabolite. ## Primary Indications * **Acetaminophen Overdose:** Prevention or mitigation of hepatotoxicity. * **Mucolytic Therapy:** As an aerosol or nebulized treatment for conditions with viscous mucus (e.g., cystic fibrosis, chronic bronchitis). ## Adult Dosing * **Acetaminophen Overdose (IV - Acetadote):** * Loading dose: 150 mg/kg over 60 minutes. * Second dose: 50 mg/kg over 4 hours. * Third dose: 100 mg/kg over 16 hours. * **Acetaminophen Overdose (Oral):** 140 mg/kg loading dose, followed by 70 mg/kg every 4 hours for 17 doses (total 18 doses). *Note: Local protocols often utilize shorter IV regimens.* * **Mucolytic (Nebulized):** 3–5 mL of 20% solution or 6–10 mL of 10% solution administered 3–4 times daily. ## Pediatric Dosing * **Acetaminophen Overdose (IV):** Same as adult dosing protocol (150 mg/kg -> 50 mg/kg -> 100 mg/kg). Weight-based dosing is critical. Ensure strict adherence to dilution protocols to prevent fluid overload. * **Mucolytic (Nebulized):** 1–2 mL of 20% solution or 2–4 mL of 10% solution diluted with saline 3–4 times daily. ## Dose Adjustments * **Renal/Hepatic:** No specific dose adjustment necessary for systemic administration, though monitor liver enzymes in overdose cases. * **Adjustment for Adverse Effects:** If a severe infusion reaction occurs during IV administration, pause the infusion, provide antihistamine/epinephrine, and restart at a slower rate once symptoms resolve. ## Contraindications * **General:** Known hypersensitivity to acetylcysteine. * **Oral/Nebulized:** Use with caution in patients with asthma or history of bronchospasm due to risk of airway irritation. ## Adverse Effects * **IV (Common/Severe):** Anaphylactoid reactions (rash, flushing, angioedema, hypotension, bronchospasm, tachycardia). These are dose-dependent and typically occur during the initial loading dose. * **Nebulized:** Bronchospasm, stomatitis, rhinorrhea, hemoptysis. * **Oral:** Nausea, vomiting (common), diarrhea, unpleasant "rotten egg" (sulfur) odor/taste. ## Key Drug Interactions * **Activated Charcoal:** May bind acetylcysteine if administered orally. If charcoal is given for multi-drug ingestion, wait 1–2 hours before starting oral acetylcysteine, or increase the dose of NAC if clinically necessary. * **Inhaled Antibiotics:** Do not mix in the same nebulizer as acetylcysteine to avoid potential degradation/inactivation. ## Monitoring * **Overdose:** Serum acetaminophen concentration (Rumack-Matthew nomogram), ALT, AST, bilirubin, PT/INR, creatinine. * **General:** Respiratory status (if nebulized), signs of anaphylactoid reaction during IV infusion. ## Clinical Pearls * **The "Rotten Egg" Smell:** The sulfur content of acetylcysteine produces a distinct odor; inform patients this is normal. * **IV vs. Oral:** IV is preferred in patients with persistent vomiting, pregnancy, or high-risk ingestions where oral administration is unreliable. * **Dilution:** When administering IV, ensure proper dilution in D5W or 0.9% NaCl to prevent hyperosmolar complications. * **Safety:** Always check if the facility uses a 20% or 10% solution for nebulization; errors in concentration are a common source of medication safety events. *** *Disclaimer: This information is for educational purposes. Dosing protocols, particularly for acetaminophen toxicity, vary significantly by institution and toxidrome severity. Always verify specific dosing, dilution, and administration guidelines with your local pharmacy department and current institutional policies.*