Acetyl%2525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252520cysteine

# Acetylcysteine ## Overview Acetylcysteine is a mucolytic agent that breaks disulfide bonds in mucus, reducing its viscosity. It also serves as an antidote for acetaminophen overdose by replenishing hepatic glutathione stores. ## Primary Indications * **Acetaminophen Overdose:** To prevent or reduce liver injury. * **Mucolytic Agent:** For conditions associated with thick mucus (e.g., cystic fibrosis, COPD, pneumonia). ## Adult Dosing * **Acetaminophen Overdose:** * **Loading Dose:** 150 mg/kg IV infused over 60 minutes. * **Second Dose:** 50 mg/kg IV infused over 60 minutes, 4 hours after the loading dose. * **Subsequent Doses:** 100 mg/kg IV infused over 16 hours (total infusion time typically 21 hours). * **Maximum Dose:** Total daily dose should not exceed 200 mg/kg or the maximum recommended for a typical adult (e.g., 10g total over 21 hours may be considered for large individuals, though specific protocols vary). * **Oral Dosing (less common):** 140 mg/kg loading dose, followed by 70 mg/kg every 4 hours for 17 doses. * **Mucolytic (Nebulized):** 3 mL of 10% or 20% solution every 3-4 hours as needed. * **Mucolytic (Oral):** 200 mg to 400 mg twice daily or three times daily. ## Pediatric Dosing * **Acetaminophen Overdose (IV):** Dosing is the same as adults based on weight (150 mg/kg, then 50 mg/kg, then 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. * **Mucolytic (Nebulized):** 1 mL of 10% or 20% solution (or weight-based equivalent, e.g., 4 mL of 10% solution for a 40 kg child) every 3-4 hours as needed. ## Dose Adjustments * **Renal Impairment:** No specific dose adjustment is usually recommended for IV acetylcysteine in acetaminophen overdose, but caution is advised. For mucolytic use, dose may need adjustment based on patient tolerance and response. * **Hepatic Impairment:** No specific dose adjustment is usually recommended for IV acetylcysteine in acetaminophen overdose. ## Contraindications * Known hypersensitivity to acetylcysteine. * Acute bronchospasm (for nebulized administration, although benefits may outweigh risks in some patients). ## Adverse Effects * **IV Administration:** Anaphylactoid reactions (rash, pruritus, angioedema, bronchospasm, dyspnea), nausea, vomiting, flushing, tachycardia, hypotension. * **Nebulized Administration:** Bronchospasm, nausea, vomiting, stomatitis, rhinorrhea. * **Oral Administration:** Nausea, vomiting, diarrhea, rash. ## Key Drug Interactions * **Activated Charcoal:** May adsorb oral acetylcysteine, reducing its absorption. Separate administration if possible. ## Monitoring * **Acetaminophen Overdose:** * **Acetaminophen and Metabolite Levels:** Monitor at appropriate intervals to assess need for continued therapy. * **Liver Function Tests (LFTs):** Baseline and daily during treatment, especially if levels are rising or symptoms of liver injury appear. * **Prothrombin Time (PT) / International Normalized Ratio (INR):** Monitor for evidence of coagulopathy. * **Renal Function and Electrolytes.** * **Clinical Status:** Signs of hepatic encephalopathy, bleeding. * **Mucolytic Use:** Respiratory status, sputum production, and clearance. ## Clinical Pearls * The IV formulation for acetaminophen overdose is typically a 20-hour regimen. * Anaphylactoid reactions are common with IV administration but are generally not a contraindication to continuing therapy, especially in life-threatening acetaminophen overdose. Pretreatment with antihistamines and slow infusion rates may mitigate symptoms. * Bronchospasm with nebulized acetylcysteine can often be managed with concurrent bronchodilator therapy. * The effectiveness of acetylcysteine for acetaminophen overdose is highly time-dependent; it is most effective when given within 8-10 hours of ingestion. *** **Disclaimer:** This information is for educational purposes only and does not constitute medical advice. Always consult the most current prescribing information and professional resources before making any treatment decisions.