Acetyl%25252525252525252525252525252525252525252525252525252525252525252525252525252520cysteine

# Acetylcysteine ## Overview Acetylcysteine is a mucolytic agent and an antidote for acetaminophen overdose. It is available intravenously, orally, and as an inhalation solution. ## Primary Indications * **Acetaminophen Overdose:** To prevent or reduce the severity of liver damage. * **Mucolytic Agent:** To thin and loosen mucus in respiratory conditions such as cystic fibrosis or chronic obstructive pulmonary disease (COPD). ## Adult Dosing ### Acetaminophen Overdose (Intravenous): * **Loading Dose:** 150 mg/kg IV infused over 1 hour. * **Second Infusion:** 50 mg/kg IV infused over 16 hours. * **Third Infusion:** 100 mg/kg IV infused over 16 hours. * **Total Duration:** 20-21 hours. * **Maximum Dose:** Specific maximums vary based on body weight and protocol. Protocols are essential for dose calculation and rate adjustments. ### Acetaminophen Overdose (Oral): * **Loading Dose:** 140 mg/kg PO. * **Subsequent Doses:** 70 mg/kg PO every 4 hours for 17 doses (total of 18 doses). * **Maximum Dose:** Specific maximums vary based on body weight and protocol. ### Mucolytic (Inhalation): * **Adults:** 1-3 mL of a 20% solution or 3-5 mL of a 10% solution nebulized every 3-4 hours. * **Adults (Bronchoscopy):** 1-2 mL of a 20% solution instilled via nebulizer. ## Pediatric Dosing ### Acetaminophen Overdose (Intravenous): * Dosing is the same as adults (150 mg/kg, 50 mg/kg, 100 mg/kg over specified times). * Dosing must be calculated *strictly* based on weight. Protocols are essential. ### Acetaminophen Overdose (Oral): * Dosing is the same as adults (140 mg/kg initial, 70 mg/kg every 4 hours for 17 doses). * Dosing must be calculated *strictly* based on weight. Protocols are essential. ### Mucolytic (Inhalation): * **Pediatrics:** 1 mL of a 20% solution or 2-3 mL of a 10% solution nebulized every 3-4 hours. ## Dose Adjustments * **Renal/Hepatic Impairment:** No specific dose adjustments are typically recommended for IV or oral use in overdose, but close monitoring for adverse effects is warranted. For mucolytic use, dose adjustments are not usually necessary. ## Contraindications * Hypersensitivity to acetylcysteine. * Risk of bronchospasm with inhaled acetylcysteine, particularly in patients with asthma. Use with caution. ## Adverse Effects * **Intravenous:** Anaphylactoid reactions (rash, urticaria, angioedema, pruritus, bronchospasm, dyspnea), nausea, vomiting, flushing, fever. * **Oral:** Nausea, vomiting, diarrhea. Odor can be a significant deterrent. * **Inhalation:** Bronchospasm, bronchoconstriction, stomatitis, nausea, vomiting, rhinorrhea. ## Key Drug Interactions * **Activated Charcoal:** May adsorb oral acetylcysteine, reducing its absorption. Administer oral acetylcysteine at least 1 hour after activated charcoal or ensure charcoal is not adhered to acetylcysteine administration. * **Nitroglycerin:** May potentiate the vasodilatory effects of nitroglycerin, leading to hypotension and headache. Co-administration should be approached with caution. ## Monitoring * **Acetaminophen Overdose:** Liver function tests (AST, ALT, bilirubin, INR), creatinine, glucose, serum acetaminophen concentration, and clinical status. * **Mucolytic Use:** Respiratory status, breath sounds, sputum production, and for signs of bronchospasm. ## Clinical Pearls * The efficacy of acetylcysteine in acetaminophen overdose is highly time-dependent. Prompt administration is critical. * Intravenous acetylcysteine may be associated with anaphylactoid reactions. Prophylactic diphenhydramine may be considered. * The foul odor of oral acetylcysteine can limit adherence. Consider flavoring or concurrent administration with juices. * Intravenous administration can be through a peripheral or central line. Central venous access is preferred for higher concentrations or prolonged infusions. * Nebulized acetylcysteine may worsen bronchospasm. Co-administration of a bronchodilator is often prudent. *** *Please verify current prescribing information and institutional protocols for definitive dosing and management guidelines.*