Triparanol (brand and developmental code names MER/29) is a 24-dehydro cholesterol reductase inhibitor, which is an enzyme involved in the biosynthesis of cholesterol. It has antitumor properties, such as decreasing proliferation and inducing apoptosis in many cancer cell lines and slowing tumor growth in a mouse xenograft model. It can also decrease Hedgehog pathway signaling in cancer cells. Triparanol was the first synthetic cholesterol-lowering drug. It was withdrawn in 1962 due to severe adverse effects such as nausea and vomiting, vision loss due to irreversible cataracts, alopecia, skin disorders (e.g., dryness, itching, peeling, and "fish-scale" texture), and accelerated atherosclerosis and is now considered to be obsolete.