Please check your internet connection and try again.
# Acetylcysteine
## Overview
Acetylcysteine (N-acetyl-L-cysteine) is a derivative of the amino acid L-cysteine. It functions primarily as a mucolytic agent by splitting disulfide bonds in mucus glycoproteins and as a glutathione precursor used as an antidote for acetaminophen toxicity.
## Primary Indications
* **Acetaminophen toxicity:** Antidote to prevent hepatotoxicity.
* **Mucolytic therapy:** Adjunct for clearance of thick, viscid secretions (e.g., COPD, cystic fibrosis, pneumonia).
* **Contrast-Induced Nephropathy (CIN) prophylaxis:** (Evidence is controversial; use discouraged by many current guidelines).
## Adult Dosing
* **Acetaminophen Toxicity (IV - Acetadote protocol):**
* Loading: 150 mg/kg in 200 mL D5W over 60 minutes.
* Second infusion: 50 mg/kg in 500 mL D5W over 4 hours.
* Third infusion: 100 mg/kg in 1000 mL D5W over 16 hours.
* *Note: Local protocols often vary; always consult the Rumack-Matthew nomogram.*
* **Mucolytic (Inhalation):** 1–10 mL of 20% solution or 2–20 mL of 10% solution via nebulizer every 2–6 hours.
## Pediatric Dosing
* **Acetaminophen Toxicity:** Same weight-based mg/kg dosing as adults (150/50/100 mg/kg). Fluid volumes must be adjusted based on the patient's weight/fluid status to avoid fluid overload.
* **Mucolytic (Inhalation):** 1–10 mL of 10% solution via nebulizer every 6–8 hours.
## Dose Adjustments
* **Renal/Hepatic:** No standardized adjustments for mucolytic use. For acetaminophen toxicity, follow established protocols regardless of baseline liver/kidney function unless severe fluid restriction is required.
## Contraindications
* **Hypersensitivity:** Known severe hypersensitivity to acetylcysteine.
* **Asthma:** Use caution in patients with asthma due to potential for bronchospasm (inhalation).
## Adverse Effects
* **IV (Anaphylactoid reactions):** Flushing, pruritus, rash, angioedema, hypotension, and bronchospasm. Most common during initial loading dose.
* **Inhalation:** Stomatitis, nausea, rhinorrhea, and bronchospasm (pre-treatment with a bronchodilator is recommended).
## Key Drug Interactions
* **Activated Charcoal:** May adsorb acetylcysteine. If both are required, administer charcoal, then provide acetylcysteine dose (adjusting for charcoal presence if directed by poison control).
* **Inhalation:** Incompatible with certain antibiotics (e.g., tetracyclines, erythromycin, amphotericin B); do not mix in the same nebulizer.
## Monitoring
* **Acetaminophen Toxicity:** Serum acetaminophen levels (via Rumack-Matthew nomogram), ALT/AST, INR/PT, creatinine, and electrolytes.
* **IV Infusion:** Monitor for signs of anaphylactoid reactions (rash, wheezing, hypotension). Stop infusion immediately if severe reaction occurs.
* **Mucolytic:** Monitor for bronchospasm and increased volume of secretions (suction may be required).
## Clinical Pearls
* **Odor:** The drug has a distinct sulfur (rotten egg) odor due to sulfide byproducts; this is normal.
* **Anaphylactoid management:** Stop the infusion, initiate symptomatic treatment (antihistamines, corticosteroids, or epinephrine if indicated), and consult pharmacy/poison center regarding restarting at a slower rate.
* **Nebulization:** Always administer a short-acting beta-agonist (e.g., albuterol) prior to or co-administered with inhaled acetylcysteine to prevent or treat bronchospasm.
***
**Educational Disclaimer:** This information is for educational purposes only. Always verify doses, contraindications, and administration protocols against current institutional guidelines, local poison control centers, and official prescribing information.
