Drugs that rely on angiotensin II play a major role in increasing blood pressure and sodium concentration. They are commonly used drugs that are popular among patients suffering from low blood pressure due to their quite rare side effects.
What is angiotensin II?
Angiotensin, known since 1940, is responsible for regulating blood pressure and is produced in the kidney and converted to angiotensin II by an enzyme from the lungs. When a drug containing this compound is administered, the effect of the original angiotensin is increased, resulting in a rapid increase in blood pressure. Various studies have demonstrated that angiotensin II leads to longer life and attenuation of disease in affected patients.
Pharmacologic Action
Angiotensin II is associated with several effects, but the most prominent is a marked increase in blood pressure. This results in improved blood flow to all organs in the body, with the kidney being a particularly “affected” organ. Angiotensin II thus does not only affect a specific organ, because the effects of taking it can be measured and felt throughout the body. The adrenal cortex is addressed by a significantly increased release of aldosterone. This in turn leads to an increased excretion of potassium ions in the so-called renal tubules. The increase in blood volume is favored by a reabsorption of water, which as a consequence leads to increased blood pressure. Furthermore, angiotensin II also directly targets the renal tubules, again increasing blood pressure. Lastly, a certain hormone in the posterior pituitary gland is released more frequently, resulting in a final increase in blood pressure. These effects on the various organs are also caused by angiotensin I, but angiotensin II works much more effectively, which means that a better effect can be achieved with the same amount of medication. If no side effects occur, angiotensin II should not affect any other organs or body functions.
Medical application and use
Angiotensin II is used in drug form exclusively to treat low blood pressure. ACE inhibitors are an alternative, but these cause side effects more frequently, so angiotensin II preparations may be an effective alternative for patients affected by side effects. In a large study conducted in 2,640 patients, 20.8% of test candidates requested discontinuation of treatment with ACE inhibitors due to side effects, whereas angiotensin II drugs led to this decision in only 12.2% of cases. Angiotensin II treatment should not be used during periods of pregnancy or even subsequent breastfeeding, among other reasons, because the child may also come into contact with the drug. Furthermore, severe heart failure of grade IV is a contraindication, and Angiotensin II should not be used for treatment if severe dysfunction of the kidney (since this organ is directly responsible for the action of Angiotensin II) or liver is present. Angiotensin II can be combined with the aforementioned ACE inhibitors, but no long-term studies are available here.
Risks and Side Effects
Angiotensin II is an active substance that rarely causes side effects in the form of medication. These include, for example, dizziness or a feeling of disorientation, which is why preparations of this type should not be taken for the first time if operating machinery is planned afterwards (such as driving a car). Furthermore, liver values may change and potassium levels may increase, although this does not necessarily have a negative effect. Angiotensin II may also cause muscle and persistent joint pain and gastrointestinal discomfort. These can manifest as diarrhea or even constipation, and a mild, persistent feeling of nausea has also been demonstrated in some patients. A visible, reddish house rash is also among the side effects of angiotensin II. All of the listed side effects occur very rarely.
