Many times have 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 features.
Diuretic - what is it?
Diuretics are also called diuretic medications. They are drugs of synthetic or herbal origin that can increase the excretion of urine by the kidneys. Due to this, together with urine, the excretion of salts and water from the body is enhanced, and the level of fluid in the cavities and tissues of the body is also reduced. Because of this, swelling decreases or disappears altogether. Diuretics are drugs that are widely used in the treatment of hypertension (elevated blood pressure). They are often used to treat mild congestive heart failure, as well as a number of liver ailments and diseases associated with circulatory disorders that provoke stagnation in the body. Often, diuretic medications are used to reduce or completely eliminate the symptoms of flatulence, which sometimes accompanies PMS or manifests itself already during menstruation. With strict adherence to the treatment regimen and dosages, diuretics do not cause severe side effects. They are quite safe to use.
Diuretics during pregnancy
Many gynecologists do not recommend drinking diuretics during pregnancy. Drugs may be unsafe for the fetus and maternal health. The negative action was discovered not so long ago. Previously, diuretic drugs were used to reduce edema in pregnant women, to counteract preeclampsia, etc.
Diuretics: classification
There are various types of diuretic medications. Each category has its own strengths and weaknesses. To date, there are such groups of drugs:
• Loop medications.
• Potassium-sparing diuretics.
• Thiazide medications.
• Thiazide-like agents.
These groups will be discussed in more detail below.
Loop diuretics
This category of drugs is the most common. It includes such drugs as Ethacrine acid, Torasemide, Furosemide, Pyrethanide, Bumetanide. Despite the fact that they can vary significantly in chemical structure, these diuretics have the same mechanism of action. These medications inhibit 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 lobe of the Henle loop. It is carried out due to the blockade of sodium, chlorine, potassium ions in the apical membrane of the tubular epithelium of cells. Due to this, the operation of the rotary countercurrent system in the kidneys is suppressed. In addition, diuretics of this type are able to dilate the vessels of the cortical substance.
Side effects of loop diuretics
The strength of the effect of these medications is unusually high: they can increase diuresis by 25%. Unlike other drugs that lose their effect with normalization of bcc, loop-type diuretics continue to function under these conditions. It is due to the strong diuretic effect that they can provoke such side effects. The most rare and severe are a drop 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: lightheadedness, nausea, weakness. The medicine "Ethacrine acid" often provokes permanent or temporary deafness, as well as neutropenia. All medications of this type, which were 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 they are especially necessary for diseases such as heart failure of the refractory type and pulmonary edema. Medications are also effective for hyponatremia, hypoalbuminemia, hypokalemia, hypochloremia, and renal failure. Loop-type diuretics continue to work when other diuretic groups and their combinations are ineffective. This is their great value. Therefore, this type is so common - a loop diuretic. What is it, we have already figured out.
Thiazide diuretics
These medications and their derivatives (Indapamide, Chlortalidone and Metolazone) are used quite often. First of all, this is due to their high absorption rate in the gastrointestinal tract, as well as a good level of patient tolerance. Thiazide diuretics are less powerful than loop, but due to the long duration of action they are indicated for people with chronic ailments such as essential arterial hypertension and mild congestive heart failure. Thiazide diuretics are prescribed for oral administration. Diuresis, as a rule, begins after 1-2 hours, but the 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 "Chlortalidone" is rather slowly absorbed, therefore its duration of action is somewhat longer. Means "Metolazone" is often very effective in patients with impaired renal function, in contrast to other medications in this category.
Potassium-sparing diuretics
There is also a potassium-retaining diuretic. What it is? These drugs are used to treat hypertension in combination with other types of drugs. They prevent excessive excretion of potassium from the body, which is a common side effect of diuretic drugs of other categories. Hypokalemia is a decrease in plasma potassium levels. It is a constant companion of thiazide diuretics, which are often prescribed for the treatment of hypertension. When the potassium level drops significantly, the patient begins to experience weakness, gets tired faster, and he develops cardiac arrhythmia. To prevent this, potassium-sparing diuretics are often prescribed along with thiazide drugs. They retain in the body along with potassium also other necessary minerals - magnesium and calcium. However, they practically do not delay the withdrawal of excess fluid and sodium. The disadvantage of potassium-sparing medications is as follows. Plasma potassium levels may increase excessively (greater 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 failure.
Use for the treatment of hypertension
Diuretics for hypertension are well established. They help to remove fluid from the body, which reduces pressure. A proven fact is that diuretic drugs are more effective for the treatment of elderly patients compared to beta-blockers. Diuretic drugs are included in the list of first-line drugs that are used to normalize blood pressure. According to the recommendations of US physicians, this category should be used for the initial treatment of hypertension (uncomplicated). Due to the great importance of controlling blood pressure, as well as reducing cardiovascular risks during treatment, special attention is paid to the metabolic effects that are characteristic of antihypertensive medications. Their influence on the course of associated ailments and organ-protective characteristics is also important.
Thiazide-like and thiazide medications for hypertension
Previously, hypertension was usually treated with loop diuretics. But now they are more used for the treatment of renal, heart failure and edema. Research results have shown good efficacy of thiazide-type drugs. They improve the prognosis of hypertension. However, the reduction in the risk of coronary complications when using these funds was not so pronounced in comparison with the expected results. The use of thiazide drugs increases the likelihood of developing arrhythmias. In some patients, even sudden arrhythmic death is possible. Also, there are frequent violations of carbohydrate and lipid metabolism, as well as hyperuricemia. The course of atherosclerosis and diabetes can be aggravated. Medications of this group are often combined with potassium-sparing diuretics.
The next level of evolution of diuretics for the treatment of hypertension is thiazide-like drugs. In particular, their ancestor synthesized in 1974, the parent drug Indapamide, proved itself well. The advantage is that thiazide-like agents have much less effect on sodium reabsorption, which means that they remove significantly less potassium from the body. Therefore, negative metabolic and diabetic effects are practically absent. It has now been proven that the Indapamide drug used in small doses, in addition to the diuretic effect, is able to play the role of a calcium antagonist due to 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 prophylactic purposes, as well as for the treatment of lesions of target organs. These drugs are often prescribed as part of combined courses of therapy. They have proven themselves well and therefore are widely used in different countries of the world.