It is thought that N-acetylcysteine may reduce the ability of generated oxygen free radicals to damage cells by scavenging them. N-acetylcysteine may also increase the biologic effects of nitric oxide by combining with nitric oxide to form S-nitrosothiol, a more stable form and potent vasodilator. It also increases the expression of nitric oxide synthesis and may improve blood flow. Oxidants activate a signal-transduction cascade and molecular response that may initiate the cell-death pathway. These pathways seem to be sensitive to the redox state of the cell and are inhibited by N-acetylcysteine, which promotes pathways that lead to repair and survival whenever cells are under oxidant stress.