menadione /men′ədi·ōn/ , a synthetic fat-soluble provitamin that can be chemically converted in the body to active vitamin K. It is used as a source of vitamin K in the treatment of hypoprothrombinemia associated with vitamin K deficiency, as occurs in hepatic or biliary disease or malabsorption syndromes, or after administration of salicylates, anticoagulants, or certain antibiotics. It is administered orally or intramuscularly. Also called vitamin K3. See also vitamin K.
