Kerylene was a drug known to Federation science by the late 23rd century. Following an outbreak of a disease inflicted on the Alpha Proxima II colony by one of the Malkus Artifacts in late 2266, USS Constellation CMO Lewis Rosenhaus suggested to USS Enterprise CMO Leonard McCoy that they used kerylene as a treatment. McCoy dismissed the idea quoting that it was proven to turn dopamine toxic, to which Rosenhaus rebutted with it only being in 5% of cases. McCoy went on to consider it as a last resort should no other treatment be forthcoming. (TOS - The Brave and the Bold, Book One novella: The First Artifact)