Acetyl%2525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252520cysteine

# Acetylcysteine ## Overview Acetylcysteine is a mucolytic agent that breaks disulfide bonds in mucoproteins, decreasing mucus viscosity. It is also an antidote for acetaminophen overdose by replenishing hepatic glutathione stores. ## Primary Indications * **Acetaminophen Overdose:** Prevention of or treatment for liver damage. * **Mucolytic Agent:** Adjunct therapy for respiratory conditions characterized by thick mucus (e.g., COPD, cystic fibrosis, pneumonia). ## Adult Dosing ### Acetaminophen Overdose * **Intravenous (IV):** Typically a 3-bag, 72-hour protocol. * **Loading Dose:** 150 mg/kg IV infused over 1 hour. * **Second Infusion:** 50 mg/kg IV infused over 4 hours. * **Third Infusion:** 100 mg/kg IV infused over 16 hours. * *Note:* Local protocols may vary; some may use a continuous infusion for the second and third bags. Maximum dose considerations are based on the initial loading dose and subsequent infusions. * **Oral (PO):** Typically a 3-bag, 72-hour protocol. * **Loading Dose:** 140 mg/kg PO. * **Subsequent Doses:** 70 mg/kg PO every 4 hours for 17 doses. * *Note:* Oral administration may be associated with significant nausea and vomiting, often requiring antiemetics. ### Mucolytic Agent * **Inhaled (Nebulizer):** 3-10 mL of a 10-20% solution, or 600 mg via nebulizer every 4-12 hours. * **Intravenous (IV):** Used in specific situations, often off-label or for prophylaxis in contrast-induced nephropathy. Dosing varies widely and is not standardized. ## Pediatric Dosing ### Acetaminophen Overdose * **Intravenous (IV):** Dosing is the same as adults (150 mg/kg, then 50 mg/kg, then 100 mg/kg over specified times). Careful calculation based on patient weight is crucial. * **Oral (PO):** Dosing is the same as adults (140 mg/kg, then 70 mg/kg every 4 hours for 17 doses). ### Mucolytic Agent * **Inhaled (Nebulizer):** * **< 1 year:** 2 mL of 10% solution BID. * **1-12 years:** 5-10 mL of 10% solution or 3-5 mL of 20% solution TID-QID. * **> 12 years:** 5-10 mL of 10% solution or 3-5 mL of 20% solution TID-QID. ## Dose Adjustments * **Renal Impairment:** No specific dose adjustment is typically recommended for IV or inhaled routes. For oral use in overdose, severe renal impairment may warrant consideration, though efficacy data is limited. * **Hepatic Impairment:** No specific dose adjustment is typically recommended for IV or inhaled routes. Acetaminophen overdose treatment remains critical. ## Contraindications * Hypersensitivity to acetylcysteine or any component of the formulation. * Active hemorrhage (relative contraindication for inhaled use due to potential bronchospasm). ## Adverse Effects * **Common:** Nausea, vomiting, stomatitis (oral); bronchospasm, bronchorrhea, rhinorrhea, urticaria, pruritus (inhaled); anaphylactoid reactions (IV, particularly with rapid infusion). * **Serious:** Severe anaphylaxis, angioedema, respiratory distress. ## Key Drug Interactions * **Activated Charcoal:** Decreases absorption of orally administered acetylcysteine. * **Nitroglycerin:** May potentiate hypotension. ## Monitoring * **Acetaminophen Overdose:** * Acetaminophen and salicylate levels. * Liver function tests (AST, ALT, bilirubin, INR). * Renal function. * Glucose levels (especially with IV administration). * **Mucolytic Agent:** * Respiratory status and mucus expectoration. * Pulmonary function tests. * Signs of bronchospasm. ## Clinical Pearls * For acetaminophen overdose, initiate treatment promptly based on estimated time of ingestion and serum acetaminophen level, especially if the level is above the treatment nomogram line. * Antiemetics are often necessary for oral administration of acetylcysteine in overdose. * Bronchospasm is a potential adverse effect of inhaled acetylcysteine. Consider co-administration of a bronchodilator. * IV acetylcysteine for acetaminophen overdose is generally preferred in patients who cannot tolerate oral medications or have significant vomiting. * The odor of acetylcysteine is characteristic of sulfur and can be unpleasant. *** **Disclaimer:** This information is intended for clinical decision support and does not replace comprehensive drug compendia. Always consult current prescribing information and institutional protocols for the most up-to-date and complete guidance.