Azilsartan medoxomil

The renin-angiotensin-aldosterone system regulates blood pressure. Angiotensin II is a peptide hormone that is a principal pressor agent in the renin-angiotensin-aldosterone system. It is a potent, direct vasoconstrictor that binds to the angiotensin II type 1 receptor (AT1 receptor) to stimulate the synthesis and release of aldosterone and promote cardiac stimulation. Angiotensin II promotes renal tubular reabsorption of sodium, resulting in water retention. It also inhibits further secretion of renin. AT1 receptors are highly expressed in vascular smooth muscle and the adrenal gland.

Azilsartan medoxomil is a prodrug that is hydrolyzed to its active metabolite, azilsartan, in the gastrointestinal tract following oral administration. Azilsartan selectively binds to AT1 receptors as an antagonist, blocking vasoconstrictor and aldosterone-secreting effects of angiotensin II. Azilsartan has more than a 10,000-fold greater affinity for the AT1 receptor than for the AT2 receptor, which is predominantly involved in cardiovascular homeostasis. Azilsartan appears to dissociate from AT1 receptors much more slowly than other ARBs, which explains its longer duration of action when compared to other ARBs.