Acetyl%252525252525252525252525252525252525252525252525252525252525252525252525252525252520cysteine

# Acetylcysteine ## Overview Acetylcysteine (N-acetylcysteine, NAC) is a mucolytic agent and an antidote for acetaminophen overdose. It is available in oral, intravenous, and nebulized formulations. * Trade names include Acetadote® (IV), Mucomyst® (oral, nebulized), Cetylev® (oral granules). ## Primary Indications 1. **Acetaminophen overdose:** To prevent or reduce hepatic toxicity. 2. **Mucolytic:** To thin and loosen mucus in the airways (e.g., cystic fibrosis, COPD, bronchitis, pneumonia). ## Adult Dosing * **Acetaminophen Overdose:** * **Oral:** Loading dose of 140 mg/kg, followed by 70 mg/kg every 4 hours for 17 doses. Maximum dose per administration is typically not specified, but total daily dose is high. * **Intravenous:** Initial bolus of 150 mg/kg over 1 hour, followed by 50 mg/kg infused over 4 hours, then 100 mg/kg infused over 16 hours. *Specific IV dosing protocols may vary by institution.* * **Maximum Doses:** For IV, the total dose should not exceed 300 mg/kg over the initial 20 hours in most protocols. Higher doses have been used but can increase the risk of anaphylactoid reactions. * **Mucolytic:** * **Nebulized:** 3 to 5 mL (20% solution) or 6 to 10 mL (10% solution) every 3 to 4 hours as needed. * **Oral:** 200 mg (e.g., with Cetylev®) every 4 hours or 600 mg once daily. *Oral formulation often used off-label for various conditions.* ## Pediatric Dosing * **Acetaminophen Overdose:** * **Oral:** Loading dose of 140 mg/kg, not to exceed 14 grams, followed by 70 mg/kg every 4 hours for 17 doses, not to exceed 7 grams per dose. * **Intravenous:** Similar to adults, adjusted for weight. The protocol is often weight-based over several infusion phases: 150 mg/kg over 1 hour, 50 mg/kg over 4 hours, then 100 mg/kg over 16 hours. *Specific IV dosing protocols may vary by institution and available formulations.* * **Mucolytic:** * **Nebulized:** 1 mL to 2 mL (20% solution) or 2 mL to 4 mL (10% solution) every 3 to 4 hours. * **Oral:** 50 mg/kg once or twice daily, up to a maximum of 600 mg/day. ## Dose Adjustments No specific dose adjustments are typically required for renal or hepatic impairment, although caution is advised in severe dysfunction, especially with intravenous administration due to potential fluid overload. ## Contraindications * Known hypersensitivity to acetylcysteine. * Certain formulations may contain excipients that preclude use in specific patient populations (e.g., latex in some nebulizer stoppers). ## Adverse Effects * **Nebulized:** Bronchospasm (especially in asthmatics), stomatitis, nausea, vomiting, rhinorrhea. * **Intravenous:** Anaphylactoid reactions (ranging from rash to bronchospasm and hypotension), nausea, vomiting, fever, flushing. * **Oral:** Nausea, vomiting, diarrhea, stomatitis. ## Key Drug Interactions * **Activated Charcoal:** May adsorb oral acetylcysteine, reducing systemic absorption. Separate administration by at least 2 hours. * **Nitroglycerin:** May potentiate the vasodilatory effects of nitroglycerin. ## Monitoring * **Acetaminophen Overdose:** * Serial serum acetaminophen levels. * Liver function tests (AST, ALT, bilirubin, INR). * Renal function tests (creatinine, BUN). * Glucose levels, especially with IV administration. * Observe for signs of hypersensitivity reactions. * **Mucolytic:** * Pulmonary status, including respiratory rate, oxygen saturation, and subjective improvement of mucus clearance. * Observe for bronchospasm. ## Clinical Pearls * The smell of acetylcysteine is characteristically unpleasant (sulfurous). * For IV administration in acetaminophen overdose, timely initiation is crucial for efficacy. Consult nomograms and local protocols. * Pretreatment with corticosteroids or bronchodilators may be considered in patients with asthma or a history of bronchospasm when using nebulized acetylcysteine. * Oral acetylcysteine as an antidote for acetaminophen overdose has a higher incidence of nausea and vomiting, which may limit its use or require antiemetics. *** *This information is intended for healthcare professionals. Always consult the most current prescribing information and institutional protocols before administering any medication.*