Review Article

N-Acetylcysteine: A Review of Clinical Usefulness (an Old Drug with New Tricks)

Table 1

N-acetylcysteine (NAC) potential mechanisms of action.

1Action on glutathioneNAC restores glutathione (cysteine is rate limiting) [5] as seen in cell and animal studies and clinically in acetaminophen overdose.

2Stabilizes proteins/DNAProtects proteins by crosslinking cysteine disulfide molecules [6]. Various mechanisms of DNA repair/protection [7] as seen in animal studies and human cell studies.

3Scavenges free radicalsScavenging property via the redox potential of thiols [8] as demonstrated in cell culture.

4Anti-inflammatory propertyReduces proinflammatory cytokines [9] as seen in animal studies.

5Antioxidant propertyReduces oxidative damage [10] as seen in cell cultures.

6Mucolytic propertySplits disulfide bonds in mucoproteins lowering viscosity [11] demonstrated in purified mucus gels and tracheal explant systems and in vitro (in a pig tracheal pouch) models.

7Mitochondrial resilienceNeurogenesis-inducing ability [12] reduces apoptosis of mitochondria [13] as demonstrated in human dental pulp cells.

8Metal chelationThiol groups provide binding sites for metals [14] in animal studies.

9Glutamate/dopamine homeostasisModulates glutamate and dopamine [15] extensive studies in humans.

10Antiviral propertiesImmune modulation, anti-NF-KB properties, and other unexplored mechanisms [16] observed in vitro and in vivo.

11Vascular endothelial growth factorInhibition of vascular permeability [17] as seen in human keratinocytes.

12Adenosine triphosphate (ATP) and nitric oxide (NO) productionIncreased ATP production in some cells like fibroblasts in vitro [18]. Increased nitric oxide production [19] as demonstrated in human studies.