Dichloroisoproterenol is also known as Dichloroisoprenaline (DCI), was the first beta blocker ever to be developed. It is non-selective for the β1-adrenergic and β2-adrenergic receptors. DCI has low potency and acts as a partial agonist/antagonist at these receptors. Dichloroisoprenaline is a racemic mixture of enantiomers.