N-Acetylcysteine

Products

N-acetylcysteine is found in numerous products, including ACC Sandoz (formerly ACC eco), Ecomucyl, Fluimucil, Mucostop, and Solmucol. The original Fluimucil was first approved in many countries in 1966. Acetylcysteine is usually administered perorally in the form of effervescent tablets, lozenges, lingual tablets, powders, granules, capsules or syrups. Injection solutions, ampoules for aerosol devices, and nasal sprays are also commercially available. N-acetylcysteine eye drops are manufactured as an extemporaneous formulation.

Structure and properties

Acetylcysteine (C5H9NO3, Mr = 163.2 g/mol) is -acetylated cysteine. It exists as a white crystalline powder or as colorless crystals and is readily soluble in water. Acetylcysteine has an unpleasant odor of sulfur (rotten eggs). A similar active ingredient is the expectorant carbocisteine, which is also derived from cysteine.

Effects

Acetylcysteine (ATC R05CB01) has mucolytic properties. It dissolves disulfide bridges in the glycoproteins of mucus, thereby decreasing viscosity. It is further antioxidant and acts as a free radical scavenger. Acetylcysteine is a prodrug of the amino acid L-cysteine. Since cysteine is a component of glutathione, endogenous glutathione stores are increased. Glutathione is an important antioxidant and detoxifies, among other things, the toxic metabolite NAPQI, which is produced in increased amounts during acetaminophen poisoning.

Indications

Respiratory diseases with viscous secretion, e.g., cough, acute or chronic bronchitis, laryngitis, sinusitis, tracheitis, bronchial asthma, cystic fibrosis (adjunctive treatment). Antidote for paracetamol poisoning. Its use in numerous other indications has been studied. Acetylcysteine is also taken as a food supplement.

Dosage

As an expectorant:

  • Adults: daily dose 600 mg
  • Children from 2 to 12 years: Daily dose 300 mg, divided into 3 individual doses.
  • Children under 2 years: contraindicated

Contraindications

  • Hypersensitivity
  • Children under 2 years of age; pregnancy and lactation according to the technical information.

Use with caution in:

  • Patients at risk for gastrointestinal bleeding because vomiting could be induced
  • Patients with bronchial asthma or hyperreactive bronchial system because bronchospasm could be induced
  • Patients with high blood pressure, because some effervescent tablets contain sodium chloride (salt).

Full precautions can be found in the drug label.

Interactions

The efficacy of some antibiotics (ampicillin, tetracyclines, macrolides, cephalosporins, aminoglycosides, amphotericin B) may be reduced by N-acetylcysteine when acetylcysteine is placed in direct contact with these agents. A time interval of 2 hours should be observed during concurrent therapy with the antibiotics. Acetylcysteine may potentiate the effects of glycerol trinitrate and forms complexes with metal ions.

Adverse effects

Possible adverse effects include gastrointestinal discomfort, e.g., nausea and vomiting due to the bad odor, heartburn, bad odor of exhaled air (hydrogen sulfide), rarely urticaria, headache, and fever. Hypersensitivity reactions and anaphylactoid reactions such as rash, pruritus, angioedema, bronchospasm, tachycardia and hypotension occur mainly with intravenous or inhalation administration.