Diuretic - what is it? Classification and principle of action of diuretics

Many have repeatedly heard such a term as "diuretic". What is it, we will try to understand below. This group of drugs has its own classification, properties and characteristics

Diuretic - what is it?

Diuretics are also called diuretic medications. They are drugs of synthetic or plant origin that can increase the excretion of urine by the kidneys. This together with urine increases the excretion of salt and water from the body , and also reduces the level of fluid in the cavities and tissues of the body. Because of this, edema decreases or disappears altogether. Diuretics are drugs that are widely used in the treatment of hypertension (increased blood pressure level). They are often used for the treatment of mild congestive heart failure, as well as a number of liver ailments and diseases associated with blood circulation disorders that provoke congestion in the body. Often, diuretic medications are used to reduce or completely eliminate the symptoms of flatulence, which sometimes accompanies PMS or manifests itself during menstruation. With strict adherence to the treatment regimen and dosages, diuretics do not cause strong side effects. They are safe enough to use.

Diuretics in pregnancy

Many gynecologists do not advise drinking diuretics during pregnancy. Drugs can be unsafe for the fetus and the health of the mother. Negative action was discovered not so long ago. Previously, diuretic drugs were used to reduce edema in pregnant women, counteract pre-eclampsia, etc.

Diuretics: classification

There are different types of diuretics. Each category has its strengths and weaknesses. To date, there are such groups of medicines:

• Loop medications.
• Potassium-sparing diuretics.
• Thiazide drugs.
• Thiazide-like drugs.

These groups will be discussed in more detail below.

Diuretics in the loop

This category of drugs is the most common. Such medicines as "Etakrinic acid", "Torasemide", "Furosemide", "Piretanid", "Bumetanid" belong to it. Despite the fact that the chemical structure, they can vary significantly, these diuretics mechanism of action are the same. These medications suppress the reabsorption of substances such as sodium, chlorine and potassium. The name "loop diuretics" is associated with their mechanism of action. Resorption occurs in the ascending share of the loop of Henle. It is carried out due to the blockade of sodium, chlorine, and potassium ions in the apical membrane of the tubular epithelium of the cells. Due to this, the operation of the rotary-counterflow system in the kidneys is suppressed. In addition, diuretics of this type are able to dilate the vessels of the cortex.

Side effects of loop diuretics

The strength of the effect of these medications is extremely high: they can increase the diuresis by 25%. Unlike other drugs that lose the effect of normalizing bcc, loop type diuretics continue to function under the given conditions. It is due to a strong diuretic action that they can provoke such side effects. The most rare and severe - a fall in blood pressure, hypovolemia, a decrease in the level of GFR and renal blood flow. Due to the increased level of excretion of hydrogen, chlorine and potassium, metabolic alkalosis is not excluded. Sometimes loop diuretics provoke hyponatremia and hypokalemia. In rare cases - hyperglycemia, hyperuricemia. Other side effects are: dizziness, nausea, weakness. The drug "Etakrinaic acid" often provokes permanent or temporary deafness, as well as neutropenia. All medications of this type, listed above, are excreted by the kidneys, metabolized in the liver.

Indications for loop diuretics

These medications are prescribed for all types of heart failure. And especially they are necessary for such diseases as heart failure of refractory type and pulmonary edema. Medications are also effective in hyponatremia, hypoalbuminemia, hypokalemia, hypochloraemia, and renal failure. Diuretics of the loop type continue to work when other groups of diuretics and their combinations are ineffective. This is their great value. Therefore this type is so widespread - a loop diuretic. What is it, we have already figured out.

Diuretics thiazide

These medications and their derivatives ("Indapamide", "Chlorthalidone" and "Metholazone") are used quite often. First of all, this is due to their high rate of absorption in the gastrointestinal tract, as well as a good level of tolerance by patients. Thiazide diuretics are less potent than loop diuretics, but because of the long duration of action they are shown to people with such chronic ailments as essential hypertension and non-severe congestive heart failure. Thiazide diuretics are prescribed for oral administration. Diuresis, as a rule, begins after 1-2 hours, but therapeutic antihypertensive effect in some cases can be observed only after 3 months of continuous treatment. The ancestor of this group is chlorothiazide. It is characterized by low fat solubility and, consequently, low bioavailability. Because of this, higher dosages of the drug are required for the therapeutic effect. The drug "Chlorthalidone" is slowly absorbed, so its duration is somewhat longer. The drug "Metholazone" is often very effective in patients with reduced renal function, unlike other medications of this category.

Diuretics potassium-sparing

There is also a potassium-preserving diuretic. What it is? These drugs are used to treat hypertension in combination with other types of medicines. They prevent the excessive excretion of potassium from the body, which is a common side effect of diuretic drugs of other categories. Hypokalemia is a decrease in the level of potassium in the plasma. It is a constant companion of thiazide diuretics, which are often prescribed for the treatment of hypertension. When the level of potassium is greatly reduced, the patient begins to experience weakness, faster fatigue, he develops a cardiac arrhythmia. To prevent this, along with thiazide drugs, potassium-sparing diuretics are often prescribed. They keep in the body along with potassium, and other necessary minerals - magnesium and calcium. At the same time, they practically do not delay the withdrawal of excess liquid and sodium. The lack of potassium-sparing medications is as follows. The level of potassium in the plasma can increase excessively (more than 5 mmol / l.). This condition is called hyperkalemia. It can cause muscle paralysis and heart rhythm disturbances, up to its complete stop. The development of pathology is most possible in patients with renal insufficiency.

Use for the treatment of hypertension

Diuretics in hypertension have proven themselves well. They help to remove fluid from the body, which reduces the pressure. The proven fact is that diuretic drugs are more effective for the treatment of elderly patients in comparison with beta-blockers. Diuretic medications are included in the list of first line drugs that are used to normalize blood pressure. According to the recommendations of US doctors, this category should be used for starting therapy of hypertension (uncomplicated). Because of the large value of blood pressure control, as well as the reduction of cardiovascular risks in treatment, special attention is paid to the metabolic effects that are characteristic of antihypertensive medications. Important is also their influence on the course of associated diseases and organoprotective characteristics.

Thiazide-like and thiazide medications for hypertension

In the past, hypertension was usually treated with loop diuretics. But now they are more used for the therapy of renal, cardiac deficiencies and edema. The results of the studies showed a good effectiveness of thiazide type drugs. They improve the prognosis of hypertension. However, the decrease in the risk of coronary complications with the use of these agents was not so pronounced in comparison with the expected results. The use of thiazide drugs increases the likelihood of arrhythmias. In some patients, even a sudden arrhythmic death is possible. Also, there are frequent violations of carbohydrate and lipid metabolism, as well as hyperuricemia. May worsen the course of atherosclerosis and diabetes. Medpreparatov this group is often combined with potassium-sparing diuretics.

The next level of evolution of diuretics for the treatment of hypertension has become thiazide-like drugs. In particular, their ancestor, the medication "Indapamid" synthesized in 1974, proved itself well. The advantage is that thiazide-like drugs have much less effect on the reabsorption of sodium, which means that much less potassium is eliminated from the body. Therefore, negative metabolic and diabetic effects are practically absent. It has now been proven that the medication "Indapamide" used in small doses, in addition to diuretic action, can act as a calcium antagonist because of vasodilator activity and stimulation of prostaglandin E2 production.

In modern conditions, thiazide and thiazide-like medications are very widely used not only to reduce blood pressure, but also for preventive purposes, as well as for the therapy of target organ lesions. These medications are often prescribed as part of a combination therapy course. They have proven themselves well and are therefore widely used in different countries of the world.