Acetyl%2525252525252525252525252525252525252520cysteine

# Acetylcysteine ## Overview Acetylcysteine (N-acetyl-L-cysteine) is a mucolytic agent and a sulfhydryl donor. It acts as a precursor for glutathione synthesis, making it the specific antidote for acetaminophen toxicity. ## Primary Indications * **Acetaminophen toxicity:** Treatment of acute ingestion or chronic overdose. * **Mucolytic therapy:** Adjunct for abnormal, viscid, or inspissated mucous secretions (e.g., cystic fibrosis, bronchitis, pneumonia). * **Renal protection:** Prophylaxis against contrast-induced nephropathy (evidence remains controversial/limited). ## Adult Dosing * **Acetaminophen Toxicity (IV Protocol):** * Loading: 150 mg/kg in 200 mL D5W over 60 minutes. * Second Dose: 50 mg/kg in 500 mL D5W over 4 hours. * Third Dose: 100 mg/kg in 1000 mL D5W over 16 hours. * *Note: Follow local institutional protocols (e.g., Rumack-Matthew nomogram).* * **Acetaminophen Toxicity (Oral Protocol):** * Loading: 140 mg/kg. * Maintenance: 70 mg/kg every 4 hours for 17 doses. * **Mucolytic (Inhalation):** 1–10 mL of 20% solution or 2–20 mL of 10% solution via nebulizer every 2–6 hours. ## Pediatric Dosing * **Acetaminophen Toxicity:** Dosage is weight-based, matching adult protocols (150/50/100 mg/kg IV or 140/70 mg/kg oral). Adjust fluid volumes based on age/weight to avoid fluid overload. * **Mucolytic:** 3–5 mL of 20% solution or 6–10 mL of 10% solution via nebulizer 3–4 times daily. ## Dose Adjustments * **Renal/Hepatic:** No specific dose adjustments are typically required for acute toxicity protocols; however, fluid status must be closely monitored in patients with renal failure. ## Contraindications * **General:** Known hypersensitivity to acetylcysteine or any component of the formulation. * **Oral/IV:** None for life-threatening acetaminophen toxicity, though caution is required in patients with severe asthma (bronchospasm risk). ## Adverse Effects * **IV/Systemic:** Anaphylactoid reactions (flushing, urticaria, angioedema, hypotension, bronchospasm). High risk during loading dose infusion. * **Inhalation:** Bronchospasm, stomatitis, rhinorrhea, nausea, and vomiting. * **General:** Distinctive "rotten egg" (sulfur) odor, which may cause nausea or gagging. ## Key Drug Interactions * **Activated Charcoal:** May adsorb acetylcysteine. Administer charcoal at least 1 hour prior to oral acetylcysteine if indicated. * **Antibiotics:** In vitro incompatibility may occur. Do not mix with tetracyclines, erythromycin, or ampicillin; administer 1 hour apart if nebulized. ## Monitoring * **Acetaminophen Toxicity:** Serum acetaminophen levels, AST/ALT, bilirubin, INR, and creatinine. Monitor for signs of anaphylactoid reaction during IV infusion. * **Mucolytic:** Monitor pulmonary function, airway clearance, and frequency of wheezing. ## Clinical Pearls * **Anaphylactoid Reaction Management:** If a reaction occurs, pause infusion, administer antihistamines (e.g., diphenhydramine) or epinephrine/albuterol as needed, then restart once the reaction is managed. * **Stability:** If the oral solution is diluted, it should be used immediately (discoloration to purple/pink is normal due to reaction with rubber/metals). * **Fluid Volume:** Pediatric patients are at high risk for hyponatremia due to hypotonic IV fluids used in the 3-bag protocol; adjust IV solution concentration for small children. *** *Disclaimer: This information is for educational purposes only. Always consult current institutional protocols, local formulary guidelines, and primary drug literature (e.g., Lexicomp, Micromedex) before prescribing or administering medication.*