Acetyl%2525252525252525252525252525252525252525252525252525252525252525252525252525252520cysteine

# Acetylcysteine ## Overview Acetylcysteine is a mucolytic agent and an antidote for acetaminophen overdose. It is available in inhaled and intravenous formulations. ## Primary Indications * **Acetaminophen overdose:** To prevent or reduce liver toxicity. * **Mucolytic agent:** To loosen thick mucus in conditions such as cystic fibrosis, chronic bronchitis, and pneumonia (inhaled formulation). ## Adult Dosing **Acetaminophen Overdose:** * **Intravenous:** * An initial loading dose of 150 mg/kg intravenously over 1 hour. * Followed by 12.5 mg/kg/hour intravenously for 4 hours. * Followed by 6.25 mg/kg/hour intravenously for 16-72 hours. * Total duration of infusion is typically 21 hours or longer, depending on acetaminophen levels and clinical status. Some protocols may continue up to 72 hours. * Maximum dose not explicitly defined for the entire course but depends on patient weight and infusion rates. * **Oral:** (Less commonly used due to gastrointestinal intolerance and lower efficacy in some severe ingestions) * An initial loading dose of 140 mg/kg orally. * Followed by 70 mg/kg orally every 4 hours for 17 doses. * Total dose: 1330 mg/kg over 72 hours. **Mucolytic (Inhaled):** * Dosing may vary based on institutional protocols. Typically 3-5 mL of a 20% solution or 5-10 mL of a 10% solution every 2-6 hours via nebulizer. ## Pediatric Dosing **Acetaminophen Overdose:** * Dosing is weight-based and identical to adult dosing, adjusted for pediatric weight. * **Intravenous:** 150 mg/kg IV over 1 hour, then 12.5 mg/kg/hour IV for 4 hours, then 6.25 mg/kg/hour IV for 16-72 hours. * **Oral:** 140 mg/kg PO, followed by 70 mg/kg PO every 4 hours for 17 doses. **Mucolytic (Inhaled):** * Dosing may vary based on institutional protocols. Typically 1-2 mL of a 20% solution or 3-5 mL of a 10% solution every 2-6 hours via nebulizer. Neonates and infants may receive lower doses. ## Dose Adjustments * No specific dose adjustments are typically needed for hepatic or renal impairment for the antidote indication in acetaminophen overdose, as the drug is primarily used to prevent toxicity. * For mucolytic use, adjustments are generally not required beyond what's dictated by the underlying condition and patient response. ## Contraindications * Known hypersensitivity to acetylcysteine or any component of the formulation. * (Inhaled): Severe bronchospasm. ## Adverse Effects * **Intravenous:** Anaphylactoid reactions (rash, urticaria, angioedema, bronchospasm, hypotension), fever, nausea, vomiting. * **Inhaled:** Bronchospasm, rhinorrhea, nausea, vomiting, stomatitis. ## Key Drug Interactions * **Activated Charcoal:** May adsorb oral acetylcysteine, reducing its efficacy; administer acetylcysteine PO at least 1 hour after activated charcoal or vice versa if concurrent administration is necessary. * **Nitroglycerin:** Potential for additive hypotension. ## Monitoring * **Acetaminophen Overdose:** * Serum acetaminophen levels (at appropriate time points post-ingestion). * Liver function tests (ALT, AST, bilirubin, INR). * Renal function and electrolytes. * Clinical status (mental status, hemodynamic stability). * **Mucolytic:** * Respiratory status (ease of breathing, sputum clearance, oxygen saturation). * For inhaled use, monitor for bronchospasm. ## Clinical Pearls * Prompt initiation of N-acetylcysteine is crucial for optimal efficacy in acetaminophen overdose management. * Dosing for intravenous acetylcysteine in acetaminophen overdose is weight-based and typically follows a specific protocol; confirm the protocol with an institution's poison control center or pharmacy. * Anaphylactoid reactions are common with IV acetylcysteine and are generally manageable with supportive care, antihistamines, and corticosteroids. Do not discontinue therapy for mild reactions. * Inhaled acetylcysteine can sometimes worsen bronchospasm; co-administration with a bronchodilator may be beneficial. *** **Disclaimer:** This information is intended for healthcare professionals and does not replace professional medical advice. Always consult the most current prescribing information and institutional protocols before administering any medication.