Acetyl%25252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252520cysteine

# Acetylcysteine ## Overview Acetylcysteine is an antidote for acetaminophen overdose and a mucolytic agent. It acts as a precursor to glutathione, replenishing hepatic glutathione stores depleted by toxic N-acetyl-p-benzoquinone imine (NAPQI) metabolite of acetaminophen. As a mucolytic, it breaks disulfide bonds in mucoproteins, reducing viscosity. ## Primary Indications * **Acetaminophen Overdose:** Treatment to prevent or reduce liver damage. * **Mucolytic:** Adjunct in managing certain respiratory conditions with excessive or thick mucus, such as chronic bronchitis, emphysema, and cystic fibrosis. ## Adult Dosing **Acetaminophen Overdose:** * **IV:** Typically administered as a loading dose of 150 mg/kg over 1 hour, followed by a maintenance infusion of 12.5 mg/kg/hour for 4 hours, and then 6.25 mg/kg/hour for the remaining 16 hours (total 21-hour infusion). Protocols may vary; consult local guidelines. Maximum dose based on initial acetaminophen ingestion amount and weight. * **PO:** 140 mg/kg loading dose, followed by 70 mg/kg every 4 hours for 17 doses. **Mucolytic:** * **Inhaled:** 3 mL to 5 mL of a 10% or 20% solution, or 1 to 2 capsules (200 mg each) via nebulizer every 3 to 4 times daily. * **Oral (Effervescent Tablets):** 200 mg to 400 mg twice daily. ## Pediatric Dosing **Acetaminophen Overdose:** * **IV:** Dosing is the same as adults (150 mg/kg IV load, then 12.5 mg/kg/hr for 4 hr, then 6.25 mg/kg/hr for 16 hr). Weight-based dosing is crucial. Consult local protocols for specific administration details and duration. * **PO:** 140 mg/kg loading dose, followed by 70 mg/kg every 4 hours for 17 doses. **Mucolytic:** * **Inhaled:** 1 mL to 2 mL of a 10% or 20% solution via nebulizer every 3 to 4 times daily. Dosing may vary based on age and severity; consult local protocols. ## Dose Adjustments No specific dose adjustments are typically required for renal or hepatic impairment for the acetaminophen overdose protocol, but caution is advised and close monitoring is essential due to potential toxicity accumulation. For mucolytic use, dose adjustments are not typically specified but may be guided by clinical response and tolerance. ## Contraindications * Hypersensitivity to acetylcysteine or any component of the formulation. * Use with caution in patients with a history of bronchospasm. ## Adverse Effects * **IV (Overdose):** Anaphylactoid reactions (rash, urticaria, pruritus, bronchospasm, dyspnea, angioedema), nausea, vomiting, flushing, tachycardia, hypotension. * **Inhaled:** Bronchospasm, rhinorrhea, nausea, vomiting, stomatitis, urticaria. * **Oral:** Nausea, vomiting, diarrhea, rash. ## Key Drug Interactions * **Activated Charcoal:** May adsorb acetylcysteine and reduce its efficacy in acetaminophen overdose if given concurrently. Separate administration by at least 1 hour. * **Nitroglycerin:** Concomitant use may potentiate the vasodilatory effects of nitroglycerin, leading to hypotension and headache. ## Monitoring * **Acetaminophen Overdose:** * **Acetaminophen and Salicylate Levels:** Monitor at appropriate intervals to guide treatment duration. * **Liver Function Tests (LFTs):** Baseline and periodic monitoring (AST, ALT, bilirubin, PT/INR) to assess for hepatotoxicity. * **Renal Function:** Monitor for changes. * **Clinical Signs and Symptoms:** Monitor for signs of liver injury or anaphylactoid reaction. * **Mucolytic Use:** * **Pulmonary Function:** Monitor for improvement in mucus clearance and respiratory status. * **Bronchospasm:** Assess for development or exacerbation. ## Clinical Pearls * Early administration of acetylcysteine following acetaminophen overdose is critical for optimal efficacy. * Anaphylactoid reactions are common with IV administration and are usually managed with supportive care and dose reduction if necessary, rather than discontinuation. * The characteristic "rotten egg" odor is normal and does not indicate degradation of the medication. * For inhaled use, warming the solution may improve patient comfort and reduce bronchospasm. --- ***Disclaimer:** This information is intended for clinical professionals and is not a substitute for professional medical advice. Always consult the most current prescribing information and institutional protocols before making clinical decisions. Dosing and recommendations may vary.*