Isoetarine is a selective short-acting β2 adrenoreceptor agonist. It can be called the "granddaughter of adrenalin" in the line of β2 agonists that gave quick relief for bronchospasm and asthma. Epinephrine (adrenalin) was the first of these, and next came isoprenaline (isoproterenol). Isoetharine was the third drug in this line, thus the third generation or granddaughter of the original.