Acetyl%252525252520cysteine

# 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 metabolite NAPQI. ## Primary Indications * Acetaminophen toxicity (oral and intravenous). * Mucolytic therapy for chronic/acute pulmonary diseases (inhalation). * Prophylaxis of contrast-induced nephropathy (evidence is controversial/weak). ## Adult Dosing * **Acetaminophen Toxicity (IV - Acetadote protocol):** * Loading: 150 mg/kg IV over 60 minutes. * Second dose: 50 mg/kg IV over 4 hours. * Third dose: 100 mg/kg IV over 16 hours. * *Note: Dosing must be tailored to local protocol and nomogram analysis.* * **Acetaminophen Toxicity (Oral):** 140 mg/kg loading dose, followed by 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 (IV):** Same weight-based regimen as adults. Use caution with fluid overload in neonates/small infants; concentration often adjusted per local hospital protocol. * **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 Impairment:** No standard dosage adjustment for toxicity protocols, though fluid status must be closely monitored in renal impairment. * **Weight-based limits:** Many facilities limit maximum weight for toxicity dosing (e.g., to 100 or 110 kg) to prevent excessive IV volume or drug load; verify local institutional guidelines. ## Contraindications * **Hypersensitivity:** Known severe hypersensitivity to acetylcysteine. * **Oral administration:** In the presence of bowel obstruction or perforation (for high-dose protocols). ## Adverse Effects * **Anaphylactoid Reactions:** Flushing, rash, pruritus, angioedema, hypotension, or bronchospasm, especially with IV infusion. * **GI:** Nausea/vomiting (common with oral administration). * **Respiratory:** Bronchospasm (inhalation; consider concomitant bronchodilator). ## Key Drug Interactions * **Activated Charcoal:** May adsorb acetylcysteine. Administer charcoal at least 1 hour prior to oral acetylcysteine if both are required for toxicity. * **Nitroglycerin:** Acetylcysteine may enhance the vasodilatory effects, leading to severe hypotension and headache. ## Monitoring * **Acetaminophen Toxicity:** Serial serum acetaminophen levels (Rumack-Matthew Nomogram), ALT/AST, bilirubin, INR, and creatinine. * **Infusion:** Monitor for signs of anaphylactoid reaction (vital signs, skin assessment) throughout IV administration. ## Clinical Pearls * **Managing Reactions:** Anaphylactoid reactions to IV acetylcysteine are dose/rate-dependent and often manageable by slowing or temporarily stopping the infusion, followed by antihistamines (e.g., diphenhydramine). * **Odor:** The drug has a strong sulfur (rotten egg) odor; inform patients of this to improve tolerability. * **Inhalation Tip:** If using as a mucolytic, always administer a short-acting beta-agonist (e.g., albuterol) 10–15 minutes prior to prevent drug-induced bronchospasm. *** **Educational Disclaimer:** This information is for educational purposes only. Clinical protocols for acetaminophen toxicity vary significantly by institution and region. Always verify exact dosing, infusion rates, and local nomograms with your facility’s current prescribing information or poison control center before administration.