Drug-induced effects on cholesterol catabolism and bile acids.

Serum cholesterol level is a reflection of whole-body cholesterol metabolism, which is tightly regulated so that cholesterol absorption and synthesis are interrelated. The actions of serum cholesterol-lowering drugs are based primarily on influencing cholesterol synthesis (statins), cholesterol absorption (ezetimibe) or bile acid synthesis (resins). A great deal of research has been targeted at developing drugs that inhibit the metabolism of cholesterol in enterocytes, such as microsomal transfer protein inhibitors and acyl-cholesterol acyl transferase inhibitors, but there are little published data regarding their effect on whole-body cholesterol metabolism in humans. Cholesterol is catabolized and excreted as neutral sterols of cholesterol into feces, and by conversion to bile acids. This review examines lipid-lowering drugs and their effect on cholesterol metabolic pathways.