On the World Health Organization's List of Essential Medicines and a prototypical drug of its class, propranolol is a non-cardioselective beta blocker and it is typically synthesized as a racemic mixture of 2 enantiomers where the S(-)-enantiomer has approximately 100 times the binding affinity for beta adrenergic receptors. It can be administered intravenously to the bloodstream or orally, where it passes through hepatic portal circulation, and enters the bloodstream to act on peripheral cells. Propranolol is a non-selective beta adrenergic antagonist used to treat hypertension, angina, atrial fibrillation, myocardial infarction, migraine, essential tremor, hypertrophic subaortic stenosis, and pheochromocytoma. It can be found under the brand names Hemangeol, Hemangiol, Inderal, and Innopran. Propranolol causes vasoconstriction via blockage or antagonism of the beta-2 adrenergic receptors. By blocking these receptors, the G protein signalling cascade is unable to occur, leading to increased levels of intracellular calcium which can then readily bind to calmodulin causing smooth muscle contraction (vasoconstriction in this case). Some side effects of using propranolol may include dizziness, tiredness, and difficulties sleeping.

Propranolol B2-Adrenergic Vasoconstriction Pathway References