Acetyl%25252525252525252525252525252525252525252525252520cysteine

# Acetylcysteine ## Overview Acetylcysteine is a mucolytic agent and the specific antidote for acetaminophen (paracetamol) toxicity. It acts as a glutathione precursor, maintaining or restoring hepatic glutathione levels required to detoxify the reactive NAPQI metabolite. ## Primary Indications * Acetaminophen overdose (oral or IV). * Adjunct therapy for abnormal, viscid, or inspissated mucous secretions (e.g., cystic fibrosis, chronic obstructive pulmonary disease). * Prevention of contrast-induced nephropathy (evidence is inconsistent/limited). ## Adult Dosing * **Acetaminophen Overdose (IV - Acetadote protocol):** * Loading: 150 mg/kg over 60 minutes. * Maintenance 1: 50 mg/kg over 4 hours. * Maintenance 2: 100 mg/kg over 16 hours. * *Total dose: 300 mg/kg over 21 hours.* * **Acetaminophen Overdose (Oral):** * 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 Overdose (IV):** Same mg/kg dosing as adults (follow specific institutional weight-based protocols to prevent fluid overload). * **Acetaminophen Overdose (Oral):** Weight-based dosing (140 mg/kg loading, followed by 70 mg/kg every 4 hours). * **Mucolytic:** 3–5 mL of 20% solution or 6–10 mL of 10% solution via nebulizer 3–4 times daily. ## Dose Adjustments * **Hepatic/Renal Impairment:** No standard adjustment required for acetaminophen toxicity; however, monitor fluid status in patients with severe heart or renal failure during high-volume IV administration. ## Contraindications * **General:** Hypersensitivity to acetylcysteine or any component of the formulation. * **Oral/Inhaled:** Avoid in patients with esophageal varices or active hemoptysis (inhaled). ## Adverse Effects * **IV:** Anaphylactoid reactions (flushing, pruritus, rash, dyspnea, hypotension), nausea, and vomiting. Usually dose-dependent or infusion-rate dependent. * **Inhaled/Oral:** Bronchospasm (more common in asthmatics), rhinorrhea, nausea, vomiting, and a distinct "rotten egg" (sulfur) odor. ## Key Drug Interactions * **Activated Charcoal:** May bind acetylcysteine if administered concurrently; administer charcoal first, wait for transit, or separate doses. * **Nitroglycerin:** Acetylcysteine may enhance the vasodilatory and antiplatelet effects, potentially causing severe hypotension and headache. ## Monitoring * **Acetaminophen Toxicity:** Serum acetaminophen levels (Rumack-Matthew nomogram), ALT/AST, bilirubin, PT/INR, creatinine, and serum electrolytes/pH. * **Infusion:** Monitor skin for rash and auscultate lungs for wheezing. If anaphylactoid reaction occurs, stop infusion, treat with antihistamines, and restart at a slower rate if clinically indicated. ## Clinical Pearls * **Infusion Site:** IV acetylcysteine may cause localized skin irritation. * **Nausea:** Oral acetylcysteine is notoriously poorly tolerated due to taste and smell; consider antiemetics (e.g., ondansetron) 30 minutes prior to administration and use a straw or dilute in juice/soda. * **Protocol Variations:** Always adhere to local institutional guidelines, as hospital-specific protocols for IV concentrations and infusion durations may vary significantly. *** **Educational Disclaimer:** This information is for educational purposes only. Clinical practice guidelines and local protocols vary. Always consult the latest prescribing information, institutional databases, and clinical pharmacists before administering medication.