Captopril emulates the function of the toxin found in Brazilian pit viper venom and is generally accepted as the first venom "success" story. Captopril is an ACE inhibitor (angiotensin converting enzyme) that was approved by the FDA approved in April 1981. It lowers blood pressure by inhibiting the production of angiotensin II which acts in a pathway that leads to vasoconstriction which raises blood pressure.