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# Acetylcysteine
## Overview
Acetylcysteine is a mucolytic agent that breaks disulfide bonds in mucoproteins, decreasing mucus viscosity. It is also an antidote for acetaminophen overdose.
## Primary Indications
* **Acetaminophen overdose:** To prevent or reduce liver toxicity.
* **Mucolytic:** To thin respiratory secretions in conditions such as cystic fibrosis, chronic bronchitis, and pneumonia.
## Adult Dosing
* **Acetaminophen Overdose:**
* **Loading Dose:** 150 mg/kg IV infused over 1 hour.
* **Second Dose:** 50 mg/kg IV infused over 4 hours.
* **Third Dose:** 100 mg/kg IV infused over 16 hours.
* *Note:* IV dosing may be adjusted based on acetaminophen levels and time from ingestion. Oral dosing is also an option, typically starting with 140 mg/kg followed by 70 mg/kg every 4 hours for 17 doses.
* **Mucolytic:**
* **Inhalation:** 3-5 mL of 10% or 20% solution every 2-6 hours as needed.
* **Nebulization:** Can be administered undiluted or diluted with sterile water or saline.
* **Oral:** 200 mg twice daily to 600 mg three times daily.
## Pediatric Dosing
* **Acetaminophen Overdose (IV):** Dosing is the same as adults (150 mg/kg IV over 1 hour, then 50 mg/kg IV over 4 hours, then 100 mg/kg IV over 16 hours).
* **Acetaminophen Overdose (Oral):** Dosing is the same as adults (140 mg/kg followed by 70 mg/kg every 4 hours for 17 doses).
* **Mucolytic (Inhalation):** 1-2 mL of 10% or 20% solution every 2-6 hours as needed.
## Dose Adjustments
No specific dose adjustments are typically required for renal or hepatic impairment, but caution is advised, especially in severe cases.
## Contraindications
* Hypersensitivity to acetylcysteine or any component of the formulation.
## Adverse Effects
* **Most Common (Inhalation):** Bronchospasm, rhinorrhea, nausea, vomiting, stomatitis.
* **Most Common (IV for Acetaminophen Overdose):** Anaphylactoid reactions (rash, urticaria, pruritus, angioedema, bronchospasm, dyspnea), nausea, vomiting.
* **Other:** Fever, headache, dizziness.
## Key Drug Interactions
* **Activated Charcoal:** Decreases absorption of oral acetylcysteine. If both are used, administer acetylcysteine at least 1 hour after activated charcoal.
* **Nitroglycerin:** May potentiate hypotensive effects.
## Monitoring
* **Acetaminophen Overdose:** Liver function tests (AST, ALT, bilirubin), prothrombin time, glucose, electrolytes, renal function, acetaminophen levels.
* **Mucolytic:** Respiratory status, sputum volume and viscosity, signs of bronchospasm.
## Clinical Pearls
* For IV administration in acetaminophen overdose, monitor closely for anaphylactoid reactions and have resuscitation equipment readily available. Pretreatment with an antihistamine may be considered.
* When nebulizing, if bronchospasm occurs, discontinue and consider a bronchodilator.
* Oral acetylcysteine has a characteristic sulfurous odor and taste, which can be unpleasant. Masking the odor with fruit juice or other beverages may improve palatability.
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*This information is intended for clinical use and does not substitute for professional medical advice. Always consult the most current prescribing information and relevant guidelines before making treatment decisions.*
