acetylcysteine (Mucomyst, Mucosol, Acetadote)

Introduction

Tradenames: Mucomyst, Mucosol, Acetadote.

Indications

• adjunctive therapy in patients with abnormal or viscid mucus secretions (bronchial secretions)
  • acute & chronic bronchopulmonary diseases
    • bronchitis, bronchiectasis, atelectasis
    • of little or no benefit in COPD (see BRONCUS study)
  • postoperative complications
    • adjunct to general anesthesia
  • cystic fibrosis
• diagnostic bronchial studies
• antidote for acute acetaminophen toxicity
• prevention of renal damage from IV contrast (contrast nephropathy)
  • useful for patients with serum creatinine below 2.0 mg/dL
• trichotillomania
• may decrease compulsive gambling and cocaine addiction
• meconium ileus
• amyloidosis

Contraindications

Caution:

• if bronchospasm occurs
  • administer a bronchodilator
  • discontinue acetylcysteine if bronchospasm progresses
• percussion, postural drainage & suction should follow administration of inhaled acetylcysteine since increased bronchial secretions may develop

pregnancy category = b

safety in lactation = ?

Dosage

• mucolytic:
  • 6-10 mL of 10% or 3-5 mL of 20% solution nebulized every 6-8 hours
  • aerosolized bronchodilator 10-15 minutes prior to acetylcholine
• oral 20% solution, 3 mL BID one day prior to & on day of procedure to prevent contrast nephropathy
• acetaminophen toxicity:
  • load 140 mg/kg PO or NG, then 70 mg/kg every 4 hours X 17 may be mixed in water or soda
  • intravenous: (Acetadote)
    • 140 mg/kg infused into a peripheral IV over 1 hour using an in-line 0.2-m millipore filter
    • maintenance doses every 4 hours of 70 mg/kg infused into a peripheral IV over 1 hour using an in-line 0.2-m millipore filter
    • IV solution made by diluting a 20% solution of acetylcysteine to 3% with D5W
    • millipore filter may be unneccesary with
  • average length of treatment is 48 hours
• trichotillomania
  • start 1200 mg PO QD; may increase to 2400 mg PO QD

Adverse effects

• common (> 10%): nausea/vomiting (foul odor)
• less common (1-10%)
  • drowsiness, chills, stomatitis, nausea, irritation, bronchospasm, rhinorrhea, hemoptysis, clamminess
• uncommon (< 1%)
  • rash, unpleasant odor during administration
• few adverse effects with IV use
  • erythema, itching & redness at IV site
  • anaphylaxis

Test interactions

• may falsely lower serum creatinine

Mechanism of action

• mucolytic activity results from splitting of disulfide linkages between mucoproteins resulting in depolymerization & a decrease in mucus viscosity
• acetylcysteine protects the liver in acetaminophen toxicity by maintaining glutathione levels & acting as a direct nucleophile reacting with the electrophilic aromatic metabolite of acetaminophen responsible for its toxicity
• modulates the glutamatergic pathway by increasing extracellular glutamate in the nucleus accumbens

More general terms

• mucolytic agent
• antidote

Additional terms

• acetaminophen poisoning
• Bronchitis Randomized on NAC Cost-Utility Study (BRONCUS)
• contrast nephropathy (contrast-induced nephropathy, CIN)

Component of

• acetylcysteine/methylcobalamin
• acetylcysteine/folic acid/methylcobalamin

Database

• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=581
• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=12035
• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=44591
• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=500198
• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=469105