Acetyl%252525252525252525252525252525252525252525252525252525252525252520cysteine

# Acetylcysteine ## Overview Acetylcysteine is a mucolytic agent that also serves as an antidote for acetaminophen overdose. It appears to restore hepatic glutathione levels depleted by the toxic metabolite of acetaminophen. ## Primary Indications * **Acetaminophen overdose:** To prevent or reduce liver damage. * **Mucolytic:** To thin and loosen mucus in respiratory conditions such as bronchitis, COPD, and cystic fibrosis. ## Adult Dosing ### Acetaminophen Overdose The optimal dose and duration depend on the time since ingestion, the acetaminophen level, and the presence of liver injury. A common regimen involves an initial IV loading dose followed by maintenance infusions. * **Standard IV Protocol (e.g., NAC Protocol):** * Loading Dose: 150 mg/kg IV over 1 hour. * Maintenance Infusion 1: 50 mg/kg IV over 4 hours. * Maintenance Infusion 2: 100 mg/kg IV over 16 hours. * *Maximum loading dose is often capped at 150 mg/kg, but specific institutional protocols may vary.* * **Oral Protocol (less common for significant ingestions due to vomiting):** * Loading Dose: 140 mg/kg PO. * Subsequent Doses: 70 mg/kg PO every 4 hours for 17 doses. * *Activated charcoal may be administered concurrently if indicated.* ### Mucolytic * **Nebulized:** 20% solution: 3-5 mL nebulized every 4-12 hours. 10% solution: 6-10 mL nebulized every 4-12 hours. * **Oral (less common):** Typically 200 mg two to three times daily. ## Pediatric Dosing ### Acetaminophen Overdose Pediatric doses follow the same weight-based calculations as adults. * **Standard IV Protocol:** * Loading Dose: 150 mg/kg IV over 1 hour. * Maintenance Infusion 1: 50 mg/kg IV over 4 hours. * Maintenance Infusion 2: 100 mg/kg IV over 16 hours. * *Infants may require dilution of the IV solution due to larger volumes.* * **Oral Protocol:** * Loading Dose: 140 mg/kg PO. * Subsequent Doses: 70 mg/kg PO every 4 hours for 17 doses. ### Mucolytic * **Nebulized:** Dosing typically adjusted based on age and weight, but often similar to adult doses (e.g., 3-5 mL of 20% solution or 6-10 mL of 10% solution). ## Dose Adjustments No specific dose adjustments are typically required for renal or hepatic impairment, as it is primarily cleared by the liver. ## Contraindications * Hypersensitivity to acetylcysteine or any component of the formulation. * Profound bronchospasm (when used as a mucolytic). ## Adverse Effects * **Anaphylactoid reactions:** Rash, pruritus, angioedema, bronchospasm, hypotension. These are more common with IV administration for acetaminophen overdose and are generally less severe with slower infusion rates. * **Nausea and vomiting:** Particularly with oral administration. * **Bronchospasm:** More likely with nebulized use in patients with reactive airway disease. * **Rhinorrhea, lacrimation, stomatitis.** ## Key Drug Interactions * **Activated Charcoal:** May adsorb oral acetylcysteine, reducing its efficacy. Separate administration times. * **Nitroglycerin:** Potential for additive hypotensive effects. Monitor blood pressure. ## Monitoring * **Acetaminophen Overdose:** * Acetaminophen levels (at baseline, 4 hours post-ingestion, and subsequent times as per protocol). * Liver function tests (AST, ALT, bilirubin, INR) regularly, especially if levels are elevated or presentation is delayed. * Renal function. * Electrolytes. * Vital signs, especially for signs of anaphylactoid reaction. * **Mucolytic Use:** * Pulmonary status (breath sounds, work of breathing, oxygen saturation). * For signs of bronchospasm. ## Clinical Pearls * Prompt initiation of acetylcysteine following acetaminophen overdose is crucial for efficacy. * Monitor for anaphylactoid reactions with IV administration; pretreatment with diphenhydramine may be considered, but acetylcysteine should not be withheld. * Dilution of IV acetylcysteine may be necessary for pediatric patients to reduce fluid load. * Consider bronchodilators to co-administer with nebulized acetylcysteine in patients with reactive airway disease. * Oral acetylcysteine can be very unpalatable and often requires antiemetics or gastric lavage. *** **Disclaimer:** This information is intended for healthcare professionals. Always consult the current official prescribing information and relevant institutional protocols for complete and up-to-date details before making clinical decisions.