Definition

The sodium salt of pravastatin with cholesterol-lowering and potential antineoplastic activities. Pravastatin competitively inhibits hepatic hydroxymethyl-glutaryl coenzyme A (HMG-CoA) reductase, the enzyme which catalyzes the conversion of HMG-CoA to mevalonate, a key step in cholesterol synthesis. This agent lowers plasma cholesterol and lipoprotein levels, and modulates immune responses by suppressing MHC II (major histocompatibility complex II) on interferon gamma-stimulated, antigen-presenting cells such as human vascular endothelial cells. In addition, pravastatin, like other statins, exhibits pro-apoptotic, growth inhibitory, and pro-differentiation activities in a variety of tumor cells; these antineoplastic activities may be due, in part, to inhibition of the isoprenylation of Ras and Rho GTPases and related signaling cascades.