Please check your internet connection and try again.
# Acetylcysteine
## Overview
Acetylcysteine is a mucolytic agent that works by breaking disulfide bonds in mucus, reducing its viscosity. It is also the antidote for acetaminophen overdose.
## Primary Indications
* Acetaminophen overdose
* Mucolytic agent for conditions associated with thick, tenacious mucus (e.g., cystic fibrosis, chronic bronchitis, pneumonia)
## Adult Dosing
### Acetaminophen Overdose
* **Loading Dose:** 150 mg/kg IV infused over 1 hour.
* **Second Dose:** 50 mg/kg IV infused over the next 4 hours.
* **Third Dose:** 100 mg/kg IV infused over the next 16 hours.
* **Maximum total dose:** Typically 300 mg/kg over 21 hours, but may be extended based on acetaminophen levels and clinical assessment.
### Mucolytic
* **Oral:** 200 mg to 400 mg (typically 200 mg capsules or 600 mg effervescent tablets) two to three times daily.
* **Nebulized:** 3 mL to 5 mL of a 10% or 20% solution every 2 to 6 hours as needed.
* **Intranasal:** 0.5 mL of a 20% solution instilled into each nostril every 3 to 4 hours as needed.
## Pediatric Dosing
### Acetaminophen Overdose
* Dosing is the same as adult dosing (150 mg/kg IV over 1 hour, then 50 mg/kg IV over 4 hours, then 100 mg/kg IV over 16 hours).
* Maximum dose should not exceed adult maximums.
### Mucolytic
* **Oral:** 10 mg/kg to 20 mg/kg (up to adult dose of 600 mg/day) divided into two to three doses daily.
* **Nebulized:** 1 mL to 2 mL of a 10% or 20% solution (or 4 mL of a 10% solution) every 2 to 6 hours as needed.
## Dose Adjustments
* No specific dose adjustments are typically required for hepatic or renal impairment for mucolytic use. For acetaminophen overdose, management is guided by serum acetaminophen levels and liver function tests.
## Contraindications
* Hypersensitivity to acetylcysteine.
* Caution with severe asthma or bronchospasm due to potential for bronchoconstriction.
## Adverse Effects
### Intravenous Administration (Acetaminophen Overdose)
* Anaphylactoid reactions (most common, ranging from rash and urticaria to bronchospasm and angioedema).
* Nausea, vomiting.
* Flushing, tachycardia, hypotension.
### Nebulized Administration
* Bronchospasm, increased airway secretions.
* Nausea, vomiting, stomatitis.
### Oral Administration
* Nausea, vomiting, diarrhea, abdominal pain.
* Rash, urticaria.
## Key Drug Interactions
* **Activated Charcoal:** May bind to oral acetylcysteine, reducing its absorption. Separate administration by at least 1 hour.
* **Nitroglycerin:** May potentiate the hypotensive effects of nitroglycerin.
## Monitoring
* **Acetaminophen Overdose:**
* Serum acetaminophen levels at appropriate intervals (e.g., 4 hours post-ingestion).
* Liver function tests (AST, ALT, bilirubin, INR) starting at 24 hours post-ingestion and repeated as clinically indicated.
* Renal function and electrolytes.
* Clinical signs of liver toxicity.
* **Mucolytic Use:**
* Pulmonary function and symptom improvement.
* Potential for bronchospasm, especially in patients with reactive airway disease.
## Clinical Pearls
* For nebulized acetylcysteine, co-administration with a bronchodilator may be beneficial to mitigate bronchospasm.
* Intravenous acetylcysteine for acetaminophen overdose should be administered with caution and appropriate monitoring for anaphylactoid reactions. Pretreatment with an H1 antagonist may be considered.
* The efficacy of acetylcysteine for acetaminophen overdose is time-dependent; prompt initiation is crucial, especially if ingestion time is unknown or exceeds 8-10 hours.
---
*This information is intended for healthcare professionals. Always consult the current prescribing information and relevant guidelines for complete and up-to-date details before making clinical decisions.*
