Please check your internet connection and try again.
# Acetylcysteine
## Overview
Acetylcysteine is a mucolytic agent used to break down thick mucus in the airways. It is also an antidote for acetaminophen overdose.
## Primary Indications
* **Acetaminophen overdose:** To prevent or reduce liver damage.
* **Mucolytic:** To thin and loosen mucus in respiratory conditions such as cystic fibrosis, COPD, and pneumonia.
## Adult Dosing
**Acetaminophen Overdose:**
* **IV:** Loading dose of 150 mg/kg infused over 1 hour, followed by 12.5 mg/kg/hour for 4 hours, then 6.25 mg/kg/hour for 16 hours. Total duration is 21 hours. Alternatively, a higher continuous infusion may be used in severe overdose or if initial doses are vomited. Specific protocols vary; consult local guidelines.
* **PO:** 140 mg/kg loading dose followed by 70 mg/kg every 4 hours for 17 doses. May be administered via nasogastric tube if vomiting occurs.
**Mucolytic:**
* **Inhaled:** 3 mL of 10% or 20% solution, or 6 mL of 10% solution, via nebulizer every 2-6 hours as needed.
* **PO:** Typically 200 mg twice daily or up to 600 mg twice daily. Dosing varies based on indication and formulation.
## Pediatric Dosing
**Acetaminophen Overdose (IV):**
* Same dosing as adults (150 mg/kg over 1 hour, then 12.5 mg/kg/hour for 4 hours, then 6.25 mg/kg/hour for 16 hours). Careful attention to infusion rate is crucial in neonates and infants.
**Acetaminophen Overdose (PO):**
* Same dosing as adults (140 mg/kg loading dose followed by 70 mg/kg every 4 hours for 17 doses).
**Mucolytic (Inhaled):**
* Typically 1 mL of 20% solution or 2-3 mL of 10% solution via nebulizer every 2-6 hours as needed. Dosing depends on the concentration used and the child's age/weight.
## Dose Adjustments
No specific dose adjustments are typically required for renal or hepatic impairment for the mucolytic indication. For acetaminophen overdose, dosing is based on weight and is not adjusted for organ dysfunction, as the goal is to overcome the toxic effects.
## Contraindications
* Hypersensitivity to acetylcysteine.
* Active bronchospasm (for inhaled form).
## Adverse Effects
* **Inhaled:** Bronchospasm, bronchoconstriction, nausea, vomiting, stomatitis, rhinorrhea, urticaria, angioedema.
* **IV:** Anaphylactoid reactions (ranging from rash to anaphylaxis), nausea, vomiting, flushing, tachycardia, hypotension. Vomiting can be severe.
* **PO:** Nausea, vomiting, diarrhea, rash.
## Key Drug Interactions
* **Activated charcoal:** May decrease absorption of oral acetylcysteine. If both are used for acetaminophen overdose, administer charcoal at least 1 hour after oral acetylcysteine.
* **Nitroglycerin:** May potentiate hypotensive effects.
## Monitoring
* **Acetaminophen Overdose:** Serum acetaminophen levels, liver function tests (ALT, AST, bilirubin), coagulation studies (INR), serum creatinine, and glucose. Monitor for signs of anaphylactoid reaction (especially with IV administration).
* **Mucolytic:** Respiratory status, sputum viscosity, and frequency of exacerbations. Monitor for bronchospasm.
## Clinical Pearls
* For IV acetylcysteine, anaphylactoid reactions are common and usually not a contraindication to continuing therapy. Premedication with an H1 or H2 antagonist may be considered.
* Dilute IV acetylcysteine in dextrose 5% in water (D5W) or normal saline (NS) to reduce the risk of hypotension and other infusion-related reactions.
* For inhaled acetylcysteine, co-administration with a bronchodilator may be beneficial to prevent bronchospasm.
* Oral acetylcysteine has an unpleasant odor (sulfur-like) which can be mitigated by mixing with flavored beverages.
* The efficacy of acetylcysteine for acetaminophen overdose is time-dependent; it is most effective when initiated within 8-10 hours of ingestion.
***
**Disclaimer:** This information is intended for healthcare professionals. Always consult the most current prescribing information and institutional protocols before administering any medication. Dosing and recommendations can vary.
