Acetyl%252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252520cysteine

# Acetylcysteine ## Overview Acetylcysteine (N-acetylcysteine, NAC) is a mucolytic agent that also functions as an antidote for acetaminophen overdose by replenishing glutathione stores. ## Primary Indications * **Acetaminophen Overdose:** To prevent or reduce liver injury following acetaminophen ingestion. * **Mucolytic:** To help thin mucus in certain respiratory conditions (e.g., chronic bronchitis, emphysema, cystic fibrosis). ## Adult Dosing * **Acetaminophen Overdose:** * **Oral:** Loading dose of 140 mg/kg, followed by 70 mg/kg every 4 hours for 17 doses (total 72 hours). Maximum initial dose 140 mg/kg. * **Intravenous (IV):** Protocol varies by institution. Common protocols involve a loading dose (e.g., 150 mg/kg over 1 hour), followed by a continuous infusion (e.g., 12.5-50 mg/kg/hour) for at least 24 hours. * **Mucolytic:** * **Oral:** 200 mg two to three times daily. * **Inhaled:** 1-10 mL of a 10-20% solution or 3-5 mL of a 20% solution nebulized every 2-6 hours. ## Pediatric Dosing * **Acetaminophen Overdose:** * **Oral:** Same as adult dosing (140 mg/kg loading dose, then 70 mg/kg every 4 hours for 17 doses). * **Intravenous (IV):** Dosing adjusted based on protocol and patient weight, often following similar principles to adult IV protocols. * **Mucolytic:** * **Inhaled:** Typically 1-10 mL of a 10-20% solution or 3-5 mL of a 20% solution nebulized every 2-6 hours. ## Dose Adjustments * No specific dose adjustments are typically required for hepatic or renal impairment, though caution is advised in severe disease. ## Contraindications * Hypersensitivity to acetylcysteine. ## Adverse Effects * **Oral:** Nausea, vomiting, diarrhea, stomatitis. * **Inhaled:** Bronchospasm, bronchoconstriction, rhinorrhea, nausea, vomiting, stomatitis. Bronchospasm is more common in patients with reactive airway disease. * **Intravenous:** Anaphylactoid reactions (rash, urticaria, angioedema, bronchospasm, hypotension), flushing, fever, chills. ## Key Drug Interactions * **Activated Charcoal:** May adsorb oral acetylcysteine, potentially reducing its efficacy in acetaminophen overdose. Separate administration by at least 1 hour. * **Nitroglycerin:** May potentiate hypotensive effects. ## Monitoring * **Acetaminophen Overdose:** * Serial liver function tests (AST, ALT, bilirubin, INR). * Acetaminophen levels. * Renal function. * **Mucolytic:** * Respiratory status, lung sounds. * Bronchospasm. ## Clinical Pearls * The IV route for acetaminophen overdose is generally preferred due to better absorption and tolerance compared to the oral route, especially in patients experiencing vomiting. * Administer inhaled acetylcysteine with a bronchodilator if the patient has a history of bronchospasm. * Anaphylactoid reactions are common with IV acetylcysteine but are generally not a contraindication to continuing therapy, especially in acetaminophen overdose. Pretreatment with an antihistamine may be considered. *** **Disclaimer:** This information is intended for educational purposes and does not substitute for professional medical advice. Always consult the most current prescribing information and institutional protocols before administering any medication.