Overview
Acetylcysteine is a mucolytic agent and antidote for acetaminophen overdose. It works by breaking down mucus in the respiratory tract and replenishing glutathione stores in the liver to prevent hepatotoxicity from acetaminophen metabolites.
Mechanism of Action
1. Mucolytic action: Breaks disulfide bonds in mucoproteins, reducing viscosity of mucus. 2. Antidotal action: Acts as a precursor for glutathione synthesis, detoxifying N-acetyl-p-benzoquinone imine (NAPQI), the toxic metabolite of acetaminophen.
Indications
- Acetaminophen overdose
- Chronic bronchitis with viscous mucus
- Cystic fibrosis with thick secretions
- Diagnostic bronchial studies
- Prevention of contrast-induced nephropathy
Dosage
Oral: For acetaminophen overdose: Loading dose 140 mg/kg, then 70 mg/kg every 4 hours for 17 doses. IV: 150 mg/kg over 1 hour, then 50 mg/kg over 4 hours, then 100 mg/kg over 16 hours. Inhalation: 3-5 mL of 20% solution 3-4 times daily.
Contraindications
- Hypersensitivity to acetylcysteine
- Active peptic ulcer disease
- Asthma without medical supervision
Side Effects
- Nausea
- Vomiting
- Rash
- Bronchospasm
- Hypotension
- Tachycardia
- Facial flushing
- Stomatitis
Interactions
- Activated charcoal may reduce oral absorption if given simultaneously
- Nitroglycerin may enhance vasodilation and hypotension
- May inactivate certain antibiotics if mixed in same nebulizer