RiteMED Acetylcysteine Mechanism of Action

Mucolytic.
Pharmacology: Pharmacodynamics: Acetylcysteine, the N-acetyl derivative of the naturally occurring amino acid, L-cysteine, is a mucolytic agent, an antidote for paracetamol poisoning and a sulfhydryl donor. Acetylcysteine has an intense mucolytic action on mucoid and mucopurulent secretions due to its ability to split disulfide bonds in mucous glycoprotein altering their configuration to improve flow characteristics thus reducing the viscosity of mucus.
Acetylcysteine has antioxidant action because of its nucleophilic free thiol (-SH) group that directly interacts with electrophilic groups of the oxidative radicals. Acetylcysteine protects α₁-antitrypsin (an enzyme that inhibits elastase) from inactivation by hypochlorous acid. Hypochlorous acid (HOCl) is a potent oxidative agent produced by the myeloperoxidase enzyme of activated phagocytes. These activities make acetylcysteine particularly appropriate for the treatment of acute and chronic conditions of the respiratory system characterized by mucoid and mucopurulent dense and viscous secretions.
Pharmacokinetics: Acetylcysteine is rapidly absorbed from the gastrointestinal tract and transported to the liver via the portal circulation, where it undergoes extensive first-pass metabolism. The oral bioavailability of acetylcysteine varies between 6 and 10%. Peak plasma concentrations are observed approximately 0.5 to 1 hour after oral doses of 200 to 600 mg.
Acetylcysteine may be present in plasma as the parent compound or as various oxidized metabolites such as N-acetylcysteine, N,N-diacetylcysteine and L-cysteine. L-cysteine itself is metabolized to glutathione, protein, taurine and sulfate. Renal clearance may account for about 30% of total body clearance. The terminal half-life of total acetylcysteine is 6.25 hours after oral dosing.