Acetyl%25252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252520cysteine

# Acetylcysteine ## Overview Acetylcysteine is a mucolytic agent that works by breaking disulfide bonds in mucus, reducing its viscosity. It is also used as an antidote for acetaminophen overdose. ## Primary Indications * **Acetaminophen Overdose:** To prevent or reduce liver damage. * **Mucolytic Agent:** To thin mucus in respiratory conditions such as bronchitis, emphysema, and cystic fibrosis. ## Adult Dosing **Acetaminophen Overdose:** * **Oral:** * **Loading Dose:** 140 mg/kg. * **Maintenance Dose:** 70 mg/kg every 4 hours for 17 doses. * Maximum dose: Generally 1000 mg per dose. * **Intravenous (IV):** * **Loading Dose:** 150 mg/kg over 1 hour. * **Second Infusion:** 50 mg/kg over 4 hours. * **Third Infusion:** 100 mg/kg over 16 hours. * Maximum rate for loading dose: 150 mg/kg/hr. Higher rates may increase the risk of anaphylactoid reactions. Local protocols may vary. **Mucolytic Agent:** * **Oral:** 200 mg twice daily to three times daily. * **Nebulization:** 1-10 mL of a 10% or 20% solution (100 mg/mL to 200 mg/mL) every 2 to 6 hours as needed. Frequency and concentration may vary based on patient response and local protocol. * **Intrapleural:** 300 mg in 10-20 mL of sterile saline instilled intrapleurally every 12-24 hours. ## Pediatric Dosing **Acetaminophen Overdose:** Dosing is the same as adult dosing, adjusted for weight. **Mucolytic Agent:** * **Nebulization:** Typically 1 mL of a 20% solution (200 mg/mL) or 2-5 mL of a 10% solution (100 mg/mL) every 2 to 6 hours. Concentration and frequency may vary based on age and local protocol. ## Dose Adjustments No specific dose adjustments are generally required for hepatic or renal impairment, though caution is advised in patients with severe impairment. ## Contraindications * Hypersensitivity to acetylcysteine or other components of the formulation. * Active bronchospasm (for nebulized formulations). ## Adverse Effects * **Common:** Nausea, vomiting, stomatitis, rash, pruritus, urticaria. * **Less Common:** Bronchospasm, rhinorrhea, drowsiness, fever, anaphylaxis (especially with IV administration). * **Rare:** Hemorrhage, angioedema. ## Key Drug Interactions * **Activated Charcoal:** May bind to oral acetylcysteine, reducing its absorption. Administer acetylcysteine at least 1 hour after activated charcoal. * **Nitroglycerin:** Increased risk of hypotension and headache. ## Monitoring * **Acetaminophen Overdose:** * Serum acetaminophen levels (at appropriate time points). * Liver function tests (AST, ALT, bilirubin, INR). * Renal function. * Electrolytes. * Clinical signs of liver toxicity. * **Mucolytic Agent:** * Respiratory status (e.g., ease of breathing, sputum production). * Bronchospasm. ## Clinical Pearls * For acetaminophen overdose, prompt administration is crucial. The initial dose is critical. * IV acetylcysteine can cause anaphylactoid reactions; premedication with an antihistamine may be considered. * Nebulized acetylcysteine can sometimes induce bronchospasm; administer with caution in patients with asthma or reactive airway disease. Bronchodilators may be co-administered. * The smell of acetylcysteine is often described as unpleasant (sulfurous). * Oral acetylcysteine is often flavored to improve palatability. Please verify current prescribing information for the most up-to-date dosing and safety guidelines.