Polyadrenaline was a synthetic version of the hormone epinephrine, also known as adrenaline. It was designed as a stimulant which could aid in the revival of a patient who had died or was near death.
Dr. Beverly Crusher used twenty-five cc polyadrenaline to assist Worf's Klingon physiology in reviving his systems after his entire spinal column was replaced by the genitronic replicator in 2368. (TNG: "Ethics")