S-nitrosothiols: a class of nitric oxide-donor drugs

Nitric oxide (NO) was originally described as the principal endothelium-der ived relaxing factor, but it is now known to subserve a variety of function s throughout the body, both physiological and pathophysiological. NO-donor drugs decompose in the body, by a variety of mechanisms, to generate NO. Su ch drugs have been used for many years in cardiovascular therapeutics, in p articular the organic nitrates for the prevention and treatment of angina p ectoris and sodium nitroprusside for the treatment of hypertensive emergenc ies. However, patients taking longterm nitrates often develop tolerance, an d prolonged nitroprusside administration can give rise to cyanide accumulat ion in the body. Newer NO-donor drugs, in particular the S-nitrosothiols, o ffer advantages over the existing drugs, since they do not share these draw backs, and initial small clinical studies suggest that they may be of benef it in a variety of cardiovascular disorders. Here we briefly review the che mistry and physiology of NO, and discuss the chemistry and clinical possibi lities of the S-nitrosothiols.