High Quality Content by WIKIPEDIA articles! Ancrod (current brand name: Viprinex) is a defibrinogenating agent derived from the venom of the Malayan pit viper. Defibrinogenating blood produces an anticoagulant effect. Ancrod is not approved or marketed in any country, but is being investigated as a stroke treatment in worldwide clinical trials. In January 2005, the U.S. Food and Drug Administration (FDA) granted `fast-track status` for investigating ancrod use in patients suffering from acute ischemic stroke, a life threatening condition caused by the blockage of blood vessels supplying blood and oxygen to portions of the brain, for which phase III trials are being conducted.