Isoprenaline (Isoproterenol / Isopropylarterenol)
Isoproterenol is a direct acting synthetic catecholamine which predominantly stimulates β1 and β2 receptors. Its main actions are seen on the heart, blood vessels of skeletal muscles and smooth muscles of bronchi and GI tract.
It decreases the peripheral resistance and increased blood flow to skeletal muscles, with little effect on cutaneous, mucosal and renal blood vessels. Overall, it lowers the blood pressure.
On the heart, isoprenaline has positive inotropic and positive chronotropic effects with increased COP and in this respect it is more potent than adrenaline and noradrenaline.
It relaxes all smooth muscles. Metabolic effects are similar to adrenaline.