Azacosterol (INNTooltip International Nonproprietary Name), or azacosterol hydrochloride (USANTooltip United States Adopted Name) (brand name Ornitrol), also known as 20,25-diazacholesterol, is a cholesterol-lowering drug (hypocholesteremic), which was marketed previously, but has since been discontinued.

[1][2][3] It is also an avian chemosterilant used to control pest pigeon populations via inducing sterility.

[5] Azacosterol acts as an inhibitor of 24-dehydrocholesterol reductase (24-DHCR), preventing the formation of cholesterol from desmosterol.

[4] Due to prevention of the metabolism of desmosterol, the drug causes it to accumulate, in turn producing side effects such as hyperkeratosis, particularly of the palms and soles.

This drug article relating to the cardiovascular system is a stub.