Acetyl%25252525252525252520cysteine

# Acetylcysteine ## Overview Acetylcysteine is a mucolytic agent that breaks disulfide bonds in mucoproteins and a precursor to glutathione, essential for replenishing hepatic stores during acetaminophen toxicity. ## Primary Indications * **Acetaminophen toxicity:** Antidote to bypass glutathione depletion. * **Mucolytic therapy:** Adjunct in respiratory conditions with abnormal, viscid, or inspissated mucous secretions (e.g., cystic fibrosis, COPD). * **Contrast-induced nephropathy (GIN) prophylaxis:** Efficacy is controversial and not universally recommended. ## Adult Dosing * **Acetaminophen Toxicity (IV - Acetadote):** * Loading: 150 mg/kg over 60 minutes. * Second dose: 50 mg/kg over 4 hours. * Third dose: 100 mg/kg over 16 hours. * *Note: Follow local institutional protocol/Rumack-Matthew nomogram for timing.* * **Acetaminophen Toxicity (Oral):** * Loading: 140 mg/kg once. * Maintenance: 70 mg/kg every 4 hours for 17 additional 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:** Same mg/kg dosing as adult IV/oral protocols. Use weight-based calculations strictly. * **Mucolytic (Inhalation):** 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 for mucolytic use. For acetaminophen toxicity, infusion rates may be modified if fluid overload occurs, but the total dose remains critical. ## Contraindications * Hypersensitivity to acetylcysteine. * Oral administration is unsafe in patients with active GI bleeding or esophageal varices. ## Adverse Effects * **Anaphylactoid reactions:** Common with IV use (flushing, urticaria, hypotension, wheezing). Stop infusion if reaction occurs; resume at slower rate or restart after antihistamines. * **Respiratory:** Bronchospasm (most common with nebulized form; pretreat with bronchodilator). * **GI:** Nausea, vomiting (common with oral protocol due to rotten-egg odor). ## Key Drug Interactions * **Activated Charcoal:** May adsorb acetylcysteine. Administer charcoal at least 1 hour prior to oral acetylcysteine; if charcoal is already given, do not necessarily withhold the antidote, but consider the potential for delayed absorption. * **Incompatibilities:** Do not mix inhaled acetylcysteine with tetracyclines, erythromycin, or amphotericin B. ## Monitoring * **Acetaminophen Toxicity:** Serum acetaminophen levels, AST/ALT, bilirubin, prothrombin time/INR, creatinine, and electrolytes. * **Mucolytic:** Monitor respiratory status, sputum consistency, and oxygen saturation. ## Clinical Pearls * **Odor:** The formulation contains sulfur, resulting in an unpleasant odor; oral doses may be diluted in juice or soda to improve palatability. * **IV Safety:** IV administration requires strict adherence to volume calculations to prevent hyponatremia and fluid overload, particularly in small children. * **Status Update:** If an allergic reaction occurs to IV acetylcysteine, it is often manageable with antihistamines and rate reduction; it is rarely an IgE-mediated anaphylaxis. *** **Educational Disclaimer:** This information is for educational purposes only. Clinical protocols vary by institution; always verify current prescribing information, institutional guidelines, and weight-based calculations via a reliable electronic database (e.g., Lexicomp, UpToDate) before prescribing or administering medication.