The drug ambrisentan is prescribed to patients suffering from pulmonary hypertension. In this rare form of hypertension, there is too much pressure exclusively in the pulmonary artery. The drug blocks the hormones that cause high blood pressure to develop.
What is ambrisentan?
Infographic on the anatomy and progression in pulmonary hypertension . Click to enlarge. The drug ambrisentan is used to treat patients who have what is known as pulmonary hypertension. This is a relatively rare form of hypertension in which the blood pressure in the pulmonary artery is moderately to severely elevated. Ambrisentan can be used regardless of whether the high blood pressure results from a disease of the connective tissue or whether the causes are unclear. The drug belongs to the relatively new group of endothelin receptor antagonists within antihypertensives. Like all drugs in this group, ambrisentan is prescribed when the elevated blood pressure can cause damage to other organs. Provided the cause of pulmonary hypertension is known, these are treated ostensibly, whereas ambrisentan may be administered as a supplement.
Pharmacologic action
The drug ambrisentan attacks directly where hypertension originates, namely at the hormonal level. Thus, hormones from the group of endothelins cause the blood vessels to contract strongly. These hormones are mainly produced in the innermost cells of blood vessels. The hormone endothelin-1 has a particularly strong influence on the cardiovascular system. The hormone exerts its effect by binding to the endothelin-A receptor, which plays a particularly important role in the development of pulmonary hypertension. The receptors to which the hormone binds are mainly located on the muscle cells of blood vessels and on the heart muscle. Ambrisentan exerts its effect by sitting on the ETA receptors, thus making it impossible for endothelin-1 to bind to the receptor. Thus, all effects of the hormone are also switched off. In addition to constricting the blood vessels, this can also lead to a proliferation of cells in the inner lining of the vessels. On the other hand, ambrisentan does not attach to receptors such as the ETB receptor. The production of porstacyclin and nitric oxide, which cause vascular slackening, is therefore unaffected by the active ingredient.
Medical application and use
The drug ambrisentan is prescribed exclusively when patients suffer from hypertension in the pulmonary artery. It lowers blood pressure by eliminating the body’s hormones that increase blood pressure. Hypertension is said to occur when several measurements indicate elevated values after a state of previous rest. In an adult, a systolic value of more than 140 mmHG or a diastolic value of more than 90 mmHG is considered the borderline between normal and high blood pressure. Those suffering from hypertension usually do not notice any symptoms. If they do, they often suffer from visual disturbances, headaches, ringing in the ears, dizziness, nosebleeds or a feeling of pressure over the heart. If high blood pressure remains untreated for years, damage to the heart, blood vessels, kidneys and brain can occur as a result. Severe kidney disorders, arteriosclerosis, strokes or a heart attack can occur as a direct result of high blood pressure. Anyone who frequently experiences the above-mentioned symptoms should have them checked by their family doctor. Furthermore, blood pressure should be measured regularly as part of routine examinations. If high blood pressure occurs during pregnancy, it must be treated as soon as possible, because otherwise seizures can occur, which can lead to life-threatening conditions and possibly also affect the unborn child.
Risks and side effects
Do not use ambrisentan in pregnant women or if patients have liver dysfunction or pulmonary fibrosis. The most common side effects of the drug include headache, fluid retention in the body, and water retention in the arms and legs. Other side effects that can occur frequently concern the cardiovascular system, such as low blood pressure or heart muscle weakness. Also mentioned are rhinitis, inflammation of the nose and throat, abdominal pain, nausea and vomiting, constipation or diarrhea. Liver enzyme levels can also increase due to the active ingredient.Occasionally, inflammation of the liver may occur, which in this case is an autoimmune disease. If water retention in the lungs develops during therapy with ambrisentan, medical attention must be sought to determine whether venous congestion may be present.
