Acetyl%25252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252520cysteine

# Acetylcysteine ## Overview N-acetylcysteine (NAC) is a mucolytic agent that also acts as an antidote for acetaminophen overdose. It works by replenishing glutathione stores in the liver, which are depleted during acetaminophen toxicity. ## Primary Indications * **Acetaminophen overdose:** To prevent or reduce liver damage. * **Mucolytic agent:** To thin and loosen mucus in respiratory conditions like cystic fibrosis, chronic bronchitis, and pneumonia. ## Adult Dosing * **Acetaminophen overdose (oral or IV):** * **Loading dose:** 150 mg/kg infused over 1 hour. * **Second dose:** 50 mg/kg infused over 4 hours. * **Third dose:** 100 mg/kg infused over 16 hours. * Maximum total dose is typically 300 mg/kg over 21 hours. Protocols may vary, and weight-based calculations are crucial. * **Mucolytic (oral):** 200 mg to 400 mg two to three times daily. * **Mucolytic (nebulized):** 3 mL to 5 mL of a 20% solution or 6 mL to 10 mL of a 10% solution every 2 to 6 hours. ## Pediatric Dosing * **Acetaminophen overdose (oral or IV):** Dosing is the same as adult dosing on a weight-based (mg/kg) calculation. Close attention to volume of infusion is needed for smaller patients. * **Mucolytic (nebulized):** 1 mL to 2 mL of a 20% solution or 2 mL to 4 mL of a 10% solution every 2 to 6 hours. ## Dose Adjustments * **Renal Impairment:** No specific dose adjustment is typically recommended, but caution is advised. * **Hepatic Impairment:** No specific dose adjustment is typically recommended for acetaminophen overdose, but liver function should be closely monitored. ## Contraindications * Hypersensitivity to acetylcysteine or any component of the formulation. * Active bronchospasm (for nebulized route). ## Adverse Effects * **Common:** Nausea, vomiting, rash, pruritus, bronchospasm, rhinorrhea. * **IV administration:** Anaphylactoid reactions (hypotension, tachycardia, angioedema), flushing. ## Key Drug Interactions * **Activated Charcoal:** May bind to oral acetylcysteine, reducing its absorption. Administer oral NAC at least 1 hour after activated charcoal. * **Nitroglycerin:** May potentiate the hypotensive effects of nitroglycerin. ## Monitoring * **Acetaminophen overdose:** Liver function tests (AST, ALT, bilirubin, INR), acetaminophen levels, renal function, glucose, and electrolytes. Monitor for signs of anaphylactoid reaction during IV infusion. * **Mucolytic:** Respiratory status, sputum volume and viscosity. ## Clinical Pearls * For IV acetylcysteine in acetaminophen overdose, prompt initiation is critical, ideally within 8 hours of ingestion. * Dilution of IV acetylcysteine is often required to reduce the risk of infusion-related reactions. Specific dilutions vary by protocol. * Smell of sulfur is characteristic and not indicative of drug degradation. * Nebulized acetylcysteine can sometimes worsen bronchospasm; co-administration with a bronchodilator may be necessary. *** *Disclaimer: This information is for educational purposes only and does not substitute professional medical advice. Always consult the current prescribing information and relevant guidelines before making any treatment decisions.*