Synonyms in a broader sense
Angiotensin converting enzyme inhibitors
Definition
This group of drugs is mainly used in the treatment of high blood pressure (arterial hypertension). Taking ACE inhibitors reduces the incidence of cardiovascular disease and lowers mortality from high blood pressure.
Fields of application
ACE inhibitors are primarily used for 3 indications, these are
- High blood pressure (hypertension)
- Heart failure (cardiac insufficiency)
- Prophylaxis of heart attacks and strokes.
Mode of action of ACE inhibitors
The renin-angiotensin system, abbreviated RAAS, serves to regulate blood pressure by producing certain hormones. If the blood pressure drops or the blood volume decreases, the system reacts by releasing renin into the blood. Renin is a protein that activates the hormone angiotensinogen.
The activated angiotensinogen is then called angiotensin 1. A protein called ACE (angiotensin-converting enzymes) acts on this hormone, resulting in the hormone angiotensin 2. Angiotensin 2 causes a general activation of the stress-mediating nervous system, which in turn leads to vasoconstriction and an increase in blood pressure.
The hormone also causes a constriction directly at the vessels, independently of the nervous system, which also leads to an increase in blood pressure. More aldosterone is also released into the bloodstream. Because of the aldosterone, the body retains more sodium and therefore more water, and the blood volume and blood pressure rise.
The ACE inhibitors intervene in this finely tuned system of blood pressure control: ACE inhibitors block the action of the protein called ACE, resulting in less production of angiotensin 2. The effect of the blockade is to lower blood pressure, because less angiotensin 2 leads to vasodilation. In addition, the release of aldosterone decreases, so that less fluid is retained in the body and the heart has less volume to pump. The lower the blood pressure, the more active the renin-angiotensin-aldosterone system is and the higher the blood pressure was before the treatment.
How do the ACE inhibitors work exactly?
The effect of this class of drugs is to reduce vascular resistance, which contributes significantly to the level of blood pressure. Vascular resistance is the pressure that the vascular system applies to the heart. The mechanism of action of ACE inhibitors is the reduced production of angiotensin 2, a hormone that leads to vasoconstriction.
Blood pressure is thus lowered by preventing the narrowing of the vessels caused by the drug. In addition, the breakdown of vasodilating hormones, the kinines, is inhibited so that vasodilatation is promoted in addition to the above mechanism. A further effect of ACE inhibitors serves to lower blood pressure: Angiotensin 2 leads to the release of aldosterone, which retains sodium (a component of common salt) and water in the body and thus increases the amount of fluid in the vascular system. ACE inhibitors, on the other hand, reduce the amount of aldosterone in the body, which results in a lower volume in the blood vessels and thus lower blood pressure. ACE inhibitors also protect the heart from the effects of stress hormones, which increase blood pressure and the heart’s oxygen consumption.
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