Olmesartan: A Selective AT1 Subtype Angiotensin II Receptor Antagonist (“sartan”)
Olmesartan, an active metabolite of olmesartan medoxomil [
O0510], is a selective AT
1 subtype angiotensin II receptor antagonist (“sartan”), such as candesartan [
C2635], eprosartan [
E1161], irbesartan [
I0859], losartan [
L0232], olmesartan [
O0507], telmisartan [
T2861] and valsartan [
V0112].
Angiotensin II is formed from angiotensin I in a reaction catalyzed by angio-tensin converting angiotensin conversion enzyme (ACE), and can active two different receptors, AT
1 and AT
2, both of which are coupled to G-protein. The vasopressor actions of angiotensin II are mediated through AT
1 receptors. Olmesartan and sartans bind selectively to AT
1 receptor with almost no binding to AT
2 receptor in vascular smooth muscle. Therefore, olmesartan and sartans show blood pressure lowering effect. Recently, some combination agents with a calcium channel antagonist (e.g. amlodipine [
A2353], azelnidipine [
A2433]) are also used for the treatment of hypertension and cardiovascular disease. (The product is for research purpose only.)