When administered into the pulmonary tree, acetylcysteine reduces
the viscosity of both purulent and nonpurulent secretions and expedites
the removal of these secretions via coughing, suction, or
postural drainage. The free sulfhydryl group on the drug is believed
to reduce disulfide linkages in mucoproteins; this effect is most pronounced
at a pH from 7 –9. The drug has no effect on living tissue
or fibrin.
Acetylcysteine can reduce the extent of liver injury or methemoglobinemia
after ingestion of acetaminophen or phenol, by providing
an alternate substrate for conjugation with the reactive metabolite
of acetaminophen, thus maintaining or restoring glutathione
levels.