Biological Activity: Isoprenaline hydrochloride is a beta-adrenergic agonist. Isoprenaline hydrochloride has a powerful stimulant action on the heart, increasing cardiac output and heart rate. Isoprenaline hydrochloride also increases blood flow to the limbs and extremities. Isoprenaline hydrochloride is a sympathomimetic medicine that dilates the small air passages in the lungs and improves the transmission of electrical signals in the heart. [1]