Acetyl%252525252525252525252525252525252525252525252525252525252525252525252525252525252525252520cysteine

# Acetylcysteine ## Overview N-acetylcysteine (NAC) is an mucolytic agent and an antidote to acetaminophen overdose. It acts by replenishing glutathione stores and directly binding to toxic metabolites. ## Primary Indications * **Acetaminophen Overdose:** Antidote. * **Mucolytic:** To thin mucus in conditions like cystic fibrosis and chronic obstructive pulmonary disease (COPD). ## Adult Dosing **Acetaminophen Overdose:** * **Loading Dose:** 150 mg/kg IV over 1 hour. * **Second Infusion:** 50 mg/kg IV over 16 hours. * **Third Infusion:** 100 mg/kg IV over 16 hours. * **Total Duration:** Typically 21 hours. Dosing may be prolonged if acetaminophen levels remain detectable or liver enzymes are elevated. **Mucolytic:** * **Oral:** 200 mg twice daily to three times daily. * **Nebulized:** 1-10 mL of a 20% solution or 2-10 mL of a 10% solution every 2-6 hours. Specific concentrations and volumes depend on local protocol or product formulation. ## Pediatric Dosing **Acetaminophen Overdose:** * Dosing is the same as adult dosing (150 mg/kg IV over 1 hour, followed by 50 mg/kg IV over 16 hours, then 100 mg/kg IV over 16 hours). Total duration is typically 21 hours. **Mucolytic:** * **Oral:** 10 mg/kg twice daily to 20 mg/kg three times daily. * **Nebulized:** 1-5 mL of a 20% solution or 2-5 mL of a 10% solution every 2-6 hours. Specific concentrations and volumes depend on local protocol or product formulation. ## Dose Adjustments * **Renal Impairment:** No specific adjustment generally recommended for IV antidote therapy. Use with caution; doses may need to be modified in severe impairment based on clinical response. * **Hepatic Impairment:** No specific adjustment generally recommended for IV antidote therapy. Monitor liver function closely. ## Contraindications * Known hypersensitivity to acetylcysteine. ## Adverse Effects **IV Administration (Antidote):** * Anaphylactoid reactions (rash, urticaria, bronchospasm, angioedema) are common, especially with rapid infusion. * Nausea and vomiting. * Less commonly: headache, fever, dizziness. **Nebulized Administration (Mucolytic):** * Bronchospasm (especially in asthmatics). * Stomatitis, nausea, vomiting. ## Key Drug Interactions * **Activated Charcoal:** Can 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. Monitor blood pressure. ## Monitoring * **Acetaminophen Overdose:** * Acetaminophen and its toxic metabolite (NAPQI) levels (obtain serum levels at specific time points as per nomogram). * Liver function tests (AST, ALT, bilirubin, PT/INR) every 24 hours. * Renal function (BUN, creatinine). * Glucose levels. * Signs of anaphylactoid reaction during IV infusion. * **Mucolytic:** * Respiratory status, lung sounds. * Signs of bronchospasm. ## Clinical Pearls * The success of NAC in acetaminophen overdose is highly dependent on timely administration. Therapy should be initiated as soon as overdose is suspected, even before laboratory confirmation. * For IV administration, slow the infusion rate if anaphylactoid reactions occur. Antihistamines and bronchodilators may be used prophylactically or for treatment. * Oral NAC has an unpleasant sulfurous odor; masking with juice or carbonated beverages may improve palatability. * Ensure the correct formulation is used for the intended route of administration. *** **Disclaimer:** This information is intended for clinical pharmacists and other healthcare professionals. It is essential to consult the most current official prescribing information, institutional protocols, and relevant literature for definitive dosing, administration, and safety guidelines. This summary is not a substitute for professional judgment.