Angiotensin II is a potent hormone that causes the muscles surrounding blood vessels to contract, thereby narrowing and constricting the blood vessels and resulting in high blood pressure. Angiotensin converting enzyme, or ACE, inhibitor medications decrease the production of angiotensin II and, as a result, blood vessels dilate, blood pressure is reduced and the heart is able to effectively circulate blood. Angiotensin II receptor blockers produce the same effects as ACE inhibitor drugs. However, angiotension II receptor blockers act by blocking the binding the angiotensin II to muscles on blood vessels as opposed to preventing the formation of angiotensin II. Since these drugs directly affect the renin angiotensin regulatory system, some side effects associated with them include acute renal failure, problems during pregnancy and angioedema.
Acute Renal Failure
Angiotensin II increases the rate at which the kidney filters waste products by increasing the glomerular filtration rate. According to the American Association of Family Physicians, the removal of angiotensin II because of ACE inhibitors or angiotension II receptor blockers results in a significant dilation of post glomerula circulation and consequently a decrease in the glomeruli filtration rate. This decrease in the ability of the kidneys to filter wastes, specifically the decrease in the glomeruli filtration rate, results in a decrease in kidney function and possibly acute renal failure.
Angioedema
Angioedema is the swelling of cutaneous and mucosal tissue because of increased vascular permeability. ACE inhibitors as well as angiotensin receptor blockers activate the degranulation of innate immune cells such as mast cells and basophils which leads to the release of other anti-inflammatory and vasodilating agents such as bradykinin and prostaglandins. The accumulation of bradykinin as a result of ACE and angiotension receptor blockers leads to increased vascular permeability, vasodilation and angioedema.
Complication With Pregnancy and Fetal Development
According to DoublecheckMD.com, angiotensin II inhibitor drugs can lead to miscarriages during the first trimester and major organ damage and possibly fetal death during the second and third trimester of pregnancy. Since angiotensin inhibitor medications directly affect the renin angiotensin system, renal failure as well as hypotension have been reported in during fetal development. Additionally, oligohydraminios, a decrease in level of amniotic fluid surrounding the fetus has also been reported perhaps due to the decrease in fetal renal function.
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