As frequently happens with scientific advances, there were several researchers working independently on what we commonly call adrenaline at around the same time in the late 1800s. The hormone is made in the body by the adrenal glands and used as a heart stimulant, anesthetic, and muscle relaxant (among many uses). In 1906, the English pharmacologist (and later Nobel laureate) Henry Dale wanted to publish his research using the word adrenaline, which was used by physiologists generically in England for the substance. Unfortunately, the American company Parke, Davis, & Co. had recently trademarked the name Adrenalin for medicinal use, and they objected to the similar adrenaline, requesting that the name used by chemists, epinephrin, should be used as a generic name instead. A third name, used by other researchers, was suprarenalin. A scientific war of words ensued, and, because precedent could be cited for use of adrenaline in scientific papers, Dale was allowed to use adrenaline, and the term continues to be used both for the substance and its figurative derivatives like adrenaline junkie and adrenaline rush.
Adrenalin is still trademarked. Epinephrin also later became the basis for a trademarked name: Epipen.