Acetyl%2525252525252525252525252525252525252525252525252525252520cysteine

# Acetylcysteine ## Overview Acetylcysteine is a mucolytic agent and a precursor to the antioxidant glutathione. It acts by splitting disulfide bonds in mucoproteins, lowering mucus viscosity, and serves as a vital antidote for acetaminophen toxicity by restoring depleted hepatic glutathione stores. ## Primary Indications * **Acetaminophen Toxicity:** Antidote to prevent hepatotoxicity. * **Mucolytic Therapy:** Adjuvant in patients with abnormal, viscid, or inspissated mucous secretions (e.g., COPD, cystic fibrosis, pneumonia). * **Contrast-Induced Nephropathy (Off-label/Controversial):** Prophylaxis in high-risk patients undergoing radiocontrast studies. ## Adult Dosing * **Acetaminophen Toxicity (IV - Acetadote protocol):** * Loading: 150 mg/kg in 200 mL D5W over 60 minutes. * Second infusion: 50 mg/kg in 500 mL D5W over 4 hours. * Third infusion: 100 mg/kg in 1000 mL D5W over 16 hours. * **Mucolytic (Inhalation/Nebulization):** 3–5 mL of 20% solution or 6–10 mL of 10% solution administered 3–4 times daily. ## Pediatric Dosing * **Acetaminophen Toxicity (IV - Weight-based):** * Loading: 150 mg/kg (infuse over 60 min). * Second infusion: 50 mg/kg (infuse over 4 hours). * Third infusion: 100 mg/kg (infuse over 16 hours). * *Note: Use age/weight-based dilution protocols to avoid fluid overload.* * **Mucolytic (Inhalation):** 1–2 mL of 20% solution or 2–4 mL of 10% solution via nebulizer 3–4 times daily. ## Dose Adjustments * **Renal/Hepatic:** No specific dose adjustments established for mucolytic use. For acetaminophen toxicity, infusion rates must be strictly followed regardless of renal/hepatic baseline function to ensure detoxification. ## Contraindications * Hypersensitivity to acetylcysteine or any component of the formulation. * Acute asthma (use with extreme caution due to bronchospasm risk). ## Adverse Effects * **IV Administration:** Anaphylactoid reactions (flushing, urticaria, angioedema, hypotension, bronchospasm), usually related to infusion rate. * **Inhalation:** Bronchospasm (pre-treat with short-acting beta-agonist), stomatitis, nausea, rhinorrhea. ## Key Drug Interactions * **Nitroglycerin:** Acetylcysteine may enhance the vasodilatory and antiplatelet effects of nitroglycerin, potentially causing severe hypotension and headache. * **Incompatibilities:** Tetracyclines, erythromycin, and amphotericin B are chemically incompatible in the same solution. ## Monitoring * **Acetaminophen Overdose:** Serum acetaminophen levels (Rumack-Matthew nomogram), ALT/AST, bilirubin, INR/PT, creatinine, and electrolytes. * **Mucolytic Use:** Monitor respiratory status (lung sounds, work of breathing) and signs of bronchospasm. ## Clinical Pearls * **Anaphylactoid Reaction Management:** If an infusion reaction occurs, stop the infusion, administer antihistamines (e.g., diphenhydramine) and rescue inhalers; restart at a slower rate if the reaction was mild and symptoms resolve. * **Sulfur Odor:** Patients may notice a "rotten egg" smell; this is characteristic of the drug and does not indicate expired medication. * **Local Protocols:** Acetaminophen toxicity protocols often vary by institution (e.g., 20-hour IV vs. 72-hour oral). Always verify the specific institutional order set. *** **Disclaimer:** This information is for educational purposes only. Clinical practice and therapeutic protocols vary by institution. Always verify dosages, contraindications, and drug interactions against the most current FDA-approved prescribing information or institutional pharmacy clinical guidelines before prescribing or administering medication.