Indications for the use of loop diuretics: mechanism of action and contraindications

Diuretics or diuretics are drugs that have the ability to remove excess fluid from the body cavity.

They are most often used in urology, nephrology, and also to combat arterial hypertension and diseases that are accompanied by edema.

It must be remembered that they excrete substances necessary for the body along with urine, which leads to the development of osteoporosis and impaired kidney function.

That is why it is recommended to give preference to those products that do not remove potassium from the body.

Main Applications

Diuretics are successfully used in nephrology and urology; they are endowed with the ability to blunt the excretion of potassium ions by the kidneys, while simultaneously preventing the excessive production of H ions and stimulating the excretion of HCO3 in the urine.

Widely used for pregnant women or hypertensive patients with various kidney diseases, such as:

• pyelonephritis;
• glomerulonephritis;
• urolithiasis, etc.

The drugs have a high level of effectiveness in the fight against hypercalcemia. The diuretic effect of the drugs is insignificant, but they prevent the loss of K and Mg by the kidneys.

For hypertension

In the treatment of arterial hypertension, potassium-sparing diuretics are prescribed in small doses, this is explained by the fact that they do not reduce blood pressure very effectively, and increasing the dosage can lead to adverse reactions.

If such treatment is ineffective, it is considered justified to prescribe additional diuretics or give preference to loop or thiazide diuretics.

During heart failure

Heart failure is characterized by fluid retention in the body. It is in this situation that the prescription of a diuretic drug that retains potassium in the body will be effective.

At the initial stages, the dose is insignificant, but over time it is increased until the patient’s weight begins to decrease. The use of drugs is considered effective if all swelling disappears.

During the period of bearing a child

Many pregnant women suffer from swelling, especially in the last trimester.

It is to eliminate this problem that doctors prescribe a special diet with limited salt and diuretics that help replenish the body's potassium reserves.

The drugs of choice in this situation are potassium-sparing diuretics, because they prevent the leaching of potassium ions from the blood.

Can it be used for hypertension?

Treatment with diuretics is of two types:

1. Active therapy - a potent diuretic is prescribed situationally.
2. Maintenance treatment is constant moderate intake of medications of this type.

Potassium-sparing diuretics are used to treat arterial hypertension. This group of diuretics has a significant drawback - their effectiveness in reducing blood pressure is low.

Potassium-sparing diuretics are rarely used for self-treatment. Prescribed in combination with loop and thiazide diuretics. The main purpose is to prevent excessive loss of potassium by the patient's body.

Mechanism of action

The drugs exhibit a high level of influence in the distal tubule of the nephron, where ion exchange occurs. Potassium-sparing diuretics prevent the penetration of sodium ions into the bloodstream, localizing them in the tubules.

Sodium has the ability to attract fluid to itself, helping to increase daily diuresis. In parallel, diuretics of this group prevent potassium ions from entering the tubules, preserving microelements in the body.

Thanks to the concentration of potassium in the body, it is possible to avoid the development of a large number of adverse reactions, and most importantly, hyperkalemia.

Please note that diuretics that retain potassium begin to have a therapeutic effect a few days after administration. For example, osmotic drugs or powerful diuretics act immediately after use. It is this feature that must be taken into account when choosing a diuretic drug.

Benefits of the drugs

The main difference between potassium-sparing diuretics and conventional diuretics is that they prevent the removal of potassium from the body along with urine. Drugs of other classes do not have this property. Potassium deficiency (hypokalemia) often leads to serious consequences.

General weakness, muscle cramps and pain, problems in the gastrointestinal tract, tachycardia, arrhythmia are manifestations that occur with hypokalemia. Such symptoms almost never develop while taking potassium-sparing diuretics.

The benefits of admission include:

• the body does not experience potassium deficiency;
• the acid-base balance is not disturbed;
• the excretion of magnesium and calcium ions decreases;
• a long-term therapeutic effect is observed;
• there is no negative effect on the cardiovascular system or kidneys.

Note! Potassium-sparing diuretics have a milder and weaker effect. To enhance the effect, they are often prescribed in combination with other diuretics.

Adverse reactions

Observational data show that adverse reactions from the use of potassium-sparing diuretics are rare. This is explained by the fact that they are prescribed in small doses.

However, they can lead to the formation of hyperkalemia; this condition can be discussed when the potassium level rises above 5.3 mmol/l. It is dangerous because it can lead to the development of fatal arrhythmias. Less commonly observed:

• the appearance of rash elements on the skin;
• dizziness;
• convulsions;
• headache;
• feeling drowsy;
• bowel disorders such as diarrhea or constipation;
• sexual problems;
• menstrual irregularities;
• excessive hair growth;
• liver dysfunction.

Compatibility with other drugs

Before starting treatment with this group of drugs, it is necessary to familiarize yourself with the compatibility of loop diuretics with other drugs.

This is because combination with a number of other drugs can provoke significant negative reactions:

• when combined with anti-inflammatory drugs, a decrease in the effectiveness of loop diuretics is observed,
• combination with blood thinning medications may cause bleeding,
• combination with a medicinal plant such as Digitalis provokes the development of heart rhythm pathologies,
• combination with Lithium provokes the formation of vomiting and diarrhea,
• when interacting with the drug Probenecid, a reaction similar to combination with anti-inflammatory drugs is observed,
• when combined with Anaprilin, the heart rate slows down,
• when combined with diabetes medications, it lowers the amount of sugar in the blood.

That is why, if the patient used loop diuretics and was also prescribed any of the medications presented, then there is no need to force things and run to the pharmacy. It is necessary to contact a medical specialist; he must prescribe a similar remedy that will not cause negative reactions.

Classification of drugs that prevent potassium excretion

Potassium-sparing agents are divided into hormonal and non-hormonal. Considered hormonal

• Amiloride;
• Triampur.

As for non-hormonal drugs, representatives of this group are:

• Veroshpiron;
• Aldactone;
• Spironaloctone.

Hormonal medications do not affect the hormone aldosterone, so they can be prescribed with confidence and without fear to people suffering from problems associated with it.

Indications

The reasons for using diuretics of the subspecies in question depend on the specific name. However, the differences are minor.

Basically the list is approximately the same:

• Acute renal failure. Dilatation of arteries at the local level, normalization of urine flow allows you to restore filtration and bring the patient out of a critical condition. It makes sense to use medications in large dosages. This increases the risk of side effects. Therefore, therapy is carried out in a hospital, under the supervision of a urologist or nephrologist (a specialist in kidney problems).
• Edema of various origins. Including peripheral ones against the background of the named renal failure. As a symptomatic drug. Bufenox is prescribed for emergency conditions. Such as cerebral edema, pulmonary edema, as a first aid medicine.
• Cirrhosis of the liver. To restore normal filtering function of the kidneys, removing excess fluid that accumulates in the abdominal cavity (ascites). Diuretics do not fundamentally change the situation.
• Poisoning with salts of heavy metals. If the aggressive chemical is eliminated by the kidneys, diuretics make the most sense.
• Heart failure in any phase. Prescribed as a way to correct the load on a muscle organ.
• Also arterial hypertension. For monotherapy or in combination with other medications (much more often).

Since loop diuretics tend to remove electrolytes quickly and in large quantities, potassium-sparing diuretics are prescribed in parallel.

They are used as correctors to reduce the likelihood of negative phenomena.

Important to keep in mind. Under no circumstances should diuretics be used for weight loss. Losing weight. This is a catastrophic mistake. Because the patient will quickly experience the toxic effects of the drugs. The weight loss effect is due to the removal of fluid. But the mass will return after the first cup of water you drink, literally within a few hours. Systematic, albeit short-term, use of diuretics of any kind will very quickly lead to renal or heart failure. Death is just around the corner.

Characteristics of diuretics

Let us consider a more detailed description of potassium-sparing medications that are more often used.

Spironolactone

The use of Spironolactone stimulates the excretion of sodium and chlorine from the body, while at the same time retaining magnesium, calcium and potassium.

Medicines should only be prescribed by a qualified physician. The indications in the vast majority of cases are swelling.

The daily dose should not exceed 200 mg, it is divided into two or three doses. Treatment therapy should continue for 2-3 weeks, after which you can take a break for 10 days and continue treatment.

The use of Spironolactone is also considered justified for hyperaldosteronism, hyperkalemia and hypomagnesemia. The daily dose should be 300 mg.

Spironolactone can be taken even by pregnant women, but only in the 11th - 111th trimester and during lactation. However, you need to remember that a small amount of diuretic passes into milk.

Eplerenone

Eplerenone compared to Spironolactone leads to fewer adverse reactions. The therapeutic effect becomes noticeable only after taking the medicine for two weeks.

Eplerenone quite often leads to an increase in the amount of cholesterol in the body and the appearance of a dry cough.

The use of the drug is prohibited if hypotension, diabetes mellitus, renal or liver failure are diagnosed, or if there is an individual intolerance to the drug.

Contraindications are also pregnancy and breastfeeding.

Triamtezid

Triametheside has a mild therapeutic effect, so it is one of the mild diuretics.

The main active ingredient is triamterene. The drug is prescribed in combination with other drugs to eliminate the manifestations of arterial hypertension.

The drug should be prescribed only by a doctor, taking into account concomitant diseases. The drug has a therapeutic effect quite quickly, the diuretic effect occurs within a quarter of an hour and continues for 12 hours.

It is recommended to take medications after meals with plenty of liquid. It is not advisable to prescribe to patients who have a history of:

• renal failure;
• decrease in the amount of sodium ions in the blood;
• urolithiasis;
• hyperkalemia.

The drug is also not used for women while pregnant. This is explained by the fact that it can lead to the development of pathologies in a fetus with a severe course.

The active ingredient of Aldactone is spirinolactone, it is considered a potassium- and magnesium-preserving agent. The daily dose can range from 100 to 200 mg, divided into 2-3 doses.

When diagnosing severe hyperaldosteronism, medications are prescribed at a dose of 300 mg per day.

Pregnant women should not be treated with Aldactone, especially in the 1st trimester. As for the 11th and 111th trimesters, taking medications is possible, but only if they are prescribed by a doctor and the benefit to the mother outweighs the risk to the fetus.

It is allowed to carry out drug therapy with the drug during breastfeeding, because it passes into breast milk in minimal quantities.

Veroshpiron

Veroshpiron is an aldosterone antagonist, the main active ingredient is spirinolactone. When diagnosing hypertension, it is recommended to take 50-100 mg once a day.

For heart failure and edema, which are excessively intense, the recommended dose can range from 100 to 200 mg. In this situation, it is recommended to combine the drug with other diuretics.

It is not recommended to take medications while breastfeeding. If there is no other way out, lactation must be interrupted during treatment.

Side effects and contraindications

All potassium-sparing diuretics are contraindicated during lactation and in the following pathologies:

• individual intolerance to the composition of the diuretic;
• increased potassium levels in the body;
• severe renal dysfunction.

If the tablets contain milk sugar, then they should not be taken if you have hypolactasia, lactase deficiency, or impaired absorption of disaccharides.

Medicines containing spirolactone should not be used if the patient has been diagnosed with the following health problems:

• Addison's disease;

  

• high sodium levels in the blood;
• anuria.

Medicines that contain eplerenone should not be taken by children or those with severe liver pathologies.

All potassium-sparing drugs should be taken with caution in old age and with diabetes.

Spirolactone and its analogues should be taken with caution if the patient is undergoing surgery using local and general anesthesia, or is receiving medications that provoke gynecomastia, as well as in the presence of the following pathologies:

• AV block;
• increased calcium levels in the blood;
• metabolic acidosis;
• liver pathologies;
• gynecomastia;
• menstruation disorder.

Drugs containing eplerenone as an active substance should be taken with caution in case of kidney dysfunction when the glomerular filtration rate is less than 50 ml per minute.

Potassium-sparing diuretics may cause the following adverse reactions:

• allergy;
• increased number of eosinophils;
• nausea, vomiting, stomach upset, stool retention;
• dizziness, headaches;
• increased potassium content in the blood, decreased sodium;
• leg cramps;
• gynecomastia;
• kidney dysfunction;
• increased levels of creatinine and urea.

Spirolactone may cause the following adverse reactions:

• abdominal pain, inflammation and ulceration of the digestive tract mucosa, gastrointestinal bleeding, intestinal colic, liver dysfunction;
• muscle spasms, impaired consciousness, lethargic sleep, drowsiness, ataxia, lethargy;
• decrease in the number of platelets and leukocytes, megaloblastosis;
• hair loss, hair growth;
• acid-base imbalance;
• urinary bleeding;
• erectile dysfunction, menstrual irregularities, bleeding from the genital tract during menopause, pain during menstruation, deepening of the voice, chest pain, malignant tumor of the mammary gland.

Medicines based on eplerenone can also cause such negative reactions as:

• dehydration;
• increased cholesterol and triglycerides;
• difficulty falling asleep;

  

• fainting, hypoesthesia;
• myocardial infarction, atrial fibrillation, increased heart rate, left ventricular failure, hypotension, thrombosis of the leg arteries;
• bloating;
• cough, pharyngitis;
• inflammation of the gallbladder;
• musculoskeletal pain;
• powerlessness, weakness;
• back pain;
• pyelonephritis;
• hyperglycemia.

If therapeutic dosages are exceeded, spirolactone can cause an overdose, which is characterized by the following symptoms:

• nausea, vomiting;
• hypotension, dizziness;
• stomach upset;
• rashes;
• hyperkalemia, which is manifested by cardiac arrhythmia, paresthesia, and muscle weakness;
• dehydration of the body;
• a decrease in the amount of sodium in the blood, which is manifested by dry mouth, thirst, drowsiness;
• increased urea content;
• hypercalcemia.

For spirolactone poisoning, the antidote is unknown, so symptomatic therapy is recommended for the victim. He needs to have his stomach pumped out and prescribed medications that will eliminate signs of dehydration and increase blood pressure.

If hyperkalemia develops, it is necessary to use potassium-removing diuretics and inject glucose with insulin into a vein. In case of a severe overdose of spirolactone, the victim is recommended to cleanse the blood using an “artificial kidney” device.

To date, there have been no cases of eplerenone overdose. Most likely, due to excess dosages, hypotension will occur and the level of potassium in the blood will increase. There is no known antidote for eplerenone poisoning, so sympathetic therapy is recommended. The diuretic cannot be removed from the body by hemodialysis, but it binds to activated charcoal.

Contraindications for use

Despite the large number of positive properties, potassium-sparing diuretics have many contraindications; their use is prohibited if:

• hypokalemia;
• decompensated liver cirrhosis;
• breathing problems;
• intolerance to the components of the drug and sulfamide derivatives.

With extreme caution and under the supervision of a physician, it is necessary to take medications for arrhythmia, as well as if there is a need to combine medications with cardiac glycosides and lithium salts.

List of drugs and method of use

The most effective and fast-acting loop drugs:

• Furosemide. Sold as tablets (40 mg) and injections (10 mg). The tablets are taken in the morning. The maximum daily dosage is 40-160 mg. The result appears after half an hour and is maintained for 4 hours. A loop diuretic in solution is prescribed for intravenous or intramuscular administration with a dosage of 20 to 40 mg. It begins to act in a couple of minutes and continues for 8 hours.
• Britomar is a loop-action diuretic tablet containing 5 or 10 mg of active substance. You can take a diuretic at any time of the day. The dosage is selected individually depending on the severity of the disease. It begins to act an hour after administration, and the duration of the effect reaches 10 hours.
• Ethacrynic acid is prescribed in the form of injections and tablets. The single dose of the diuretic is 50 mg, but sometimes it can be increased according to indications. The therapeutic effect occurs after half an hour and lasts up to 8 hours.
• Diuver is a loop diuretic available in dosages of 10 and 5 mg. It is prescribed individually, taking into account the type of disease with a duration of action of up to 12 hours.
• Bufenox is sold in tablet form (1 mg) and injections for intramuscular and intravenous administration (0.1-0.5 mg). The initial dose is 1 tablet once a day for 4 days. Subsequent - up to 2 tablets for 3 days. The effect occurs after about 2 hours. Injections are administered at intervals of 4-6 hours. The treatment course lasts 3-4 days.
• Lasix is ​​a loop diuretic in tablets (40 mg) and injections. Prescribed depending on the disease. It begins to act after 2 hours. If blood pressure rises, injections are given twice a day.

All loop diuretics are prescribed by a doctor. Diuretic injections are given in emergency cases in severe cases of illness.