Diuretics
Synonyms in a broader sense
Water tablets, dehydration drugs, furosemide, thiazides
English:
diuretics
definition
Diuretics are a group of drugs that cause increased urine output (diuresis). They are often referred to as "water tablets" because they increase the excretion of fluids through the kidneys. They are used in the treatment of high blood pressure, for the flushing of fluids from the body, e.g. thick legs (leg edema) and when the heart function is restricted (heart failure).
When are diuretics prescribed?
They are used to treat high blood pressure (Arterial hypertension) Always given in combination with other medications and in a low dose, as the administration of diuretics alone only causes a moderate decrease in blood pressure.
Fluid retention in the body, also called Edema can e.g. in pregnancy, with loss of pumping function of the heart (Heart failure/ Heart failure) and kidney disease. The nephrotic syndrome is an important kidney disease in which water retention occurs:
The patients excrete more proteins in the urine, there are fewer proteins in the blood and there are edema, mostly of the legs. But it also often happens Water in your feet.
Under what conditions should diuretics not be taken?
Diuretics should not be taken if the patient is low on fluids. In the case of increased or decreased blood salt values, diuretics should also not be used or should be used with the patient carefully monitored. Patients tend to have bleeding disorders with the formation of blood clots in the vessels, a so-called thrombosis, diuretics should not be taken, as the excretion of water thickens the blood and makes it easier for a thrombosis to occur.
Diuretics are not given in the event of severe kidney and liver damage.
Note: drug allergy
In addition, the general rule is that drugs to which the patient has had an allergic reaction should not be prescribed again! The danger of an extended allergic reaction is too big and should not be entered.
How diuretics work
The individual classes of substances have different sites of action in the kidneys, but they all have in common that their effect increases the excretion of sodium in the urine. Sodium is a blood salt that is filtered out of the blood by the kidneys and released from the body in the urine. Due to the influence of medication, the sodium in the body decreases. The body also loses the stored water:
Patients have to go to the toilet more often because the body excretes more water along with the sodium.
Due to the possible side effects of this group of drugs, it is important to regularly check blood salts, blood sugar, blood lipids and cholesterol as well as the Kidney values when a patient is being treated with diuretics.
Different groups of drugs
Three different groups (substance classes) of diuretics are given to promote water excretion:
- Loop diuretics
- Thiazides
- Potassium-sparing diuretics
In the following, the different types of diuretics are presented in more detail and their special mode of action and their side effects are described
Loop diuretics
In the treatment of high blood pressure, this group of drugs can also be used in patients whose kidney function is already impaired. With the help of a marker in the blood, the creatinine level, kidney function can be assessed and a decision can be made as to whether the patient has such functional impairment or not.
The effect of loop diuretics can be increased by administering another drug to promote water excretion, whereby the loop diuretics are already very effective dehydration drugs.
If there is a need for rapid flushing out of liquid, e.g. if the heart failure suddenly deteriorates, this group of drugs is usually used.
Loop diuretics: active ingredient and trade names
- Bumetanide, e.g. Burinex®
- Furosemide, e.g. Lasix®®, Furorese®
- Torasemide, e.g. Torem®, Unat®, Toacard®
- Piretanide, e.g. Arelix®, piretanide 1 A®
- Etacrynic acid, e.g. Hydromedin®
Treatment with loop diuretics can decrease the levels of potassium and calcium in the blood. Both are important blood salts. If the diuretics are given together with an ACE inhibitor, care must be taken to ensure that the blood pressure does not drop too much. Both drugs reduce the amount of fluid in the body, which is accompanied by a decrease in blood pressure. This can lead to dizziness and a feeling of weakness.
Loop diuretics can be used in people with diabetes.
Thiazides
The thiazides are the so-called first-line agents in high blood pressure therapy, i.e. they are prescribed in the first place for combination treatment. Studies have shown their beneficial effects on blood pressure and a significant improvement in the prognosis for high blood pressure patients.
This group of drugs is well suited for the long-term therapy of patients with heart failure and high blood pressure.
In addition to the increased sodium excretion, effects on the blood vessels in the sense of vasodilating effects can be observed, which support the lowering of blood pressure.
Thiazides: active ingredient and trade names
- Chlorthalidone, e.g. Hygroton®
- Hydrochlorothiazide, e.g. Disalunil®, Esidrix®
- Indapamide, e.g. Inda Puren®, Sicco®
- Xipamide, e.g. Aquaphor®, Aquex®
In 20% of cases, thiazides lower the sodium, potassium and magnesium levels in the blood. The thiazides are therefore often combined with potassium-sparing diuretics to compensate for the loss of potassium. This can lead to serious cardiac arrhythmias. Metabolic disorders in the form of increased blood sugar and blood lipid levels are possible side effects of therapy with thiazides. It can also lead to nausea and vomiting.
Thiazides should not be given if kidney function is impaired because in this situation they can reduce blood flow to the kidneys, which could cause additional damage to the kidneys
Potassium-sparing diuretics
In contrast to the other diuretics, the potassium-sparing drugs cause a retention of potassium in the body and not the increased excretion of this blood salt. So it saves potassium for the body, hence the name of the drug group.
The potassium savers are used in combination with thiazides because they only cause a moderate excretion of water.
Potassium-sparing diuretics must not be given to patients with severe renal impairment, renal insufficiency.
In the case of combined treatment with ACE inhibitors and the administration of potassium, it should be noted that the body loses less potassium as a result of the effects of the potassium-sparing medication. An increased potassium level can have serious consequences such as Arrhythmias, which is why blood tests should be done at regular intervals to check potassium levels.
There are two types of drugs in this group: the aldosterone antagonists and the two drugs triamterene and amiloride.
- Aldosterone antagonists
The drugs in this group prevent aldosterone from working in the body:
Aldosterone increases the amount of fluid that is in the vessels and thus increases blood pressure. The aldosterone antagonists lead to a reduction in the volume in the vessels and thus to a lower blood pressure.
This group of diuretics is of great importance for the treatment of heart failure:
When an aldosterone antagonist is given together with an ACE inhibitor and a cardiac glycoside, it helps to lower the mortality rate in patients with severe cardiac dysfunction.
Aldosterone antagonists: active ingredient and trade names
- Eplerenone, e.g. Inspra®
- Potassium canrenoate, e.g. Aldactone®
- Spironolactone, e.g. Duraspiron®, Verospiron®
The side effects of aldosterone antagonists include an increase in potassium in the blood, possible allergic reactions, as well as nausea, vomiting and diarrhea.
- Amiloride and triamterene
These two active ingredients should also always be given together with preparations to other drug groups, as their effect would be too weak without a combination partner. Amiloride and triamterene are therefore usually given in combination with thiazides or a preparation is prescribed that contains both active ingredients (thiazide and potassium-sparing drug). This group of drugs is used to flush fluid out of the body and to treat high blood pressure.
Triamterene and amiloride: active ingredient and trade names
- Triamterene, e.g. Arumil®
- Amiloride, e.g. Jatropur®
Unwanted effects are an increase in potassium in the blood and possible allergic skin reactions or digestive tract complaints such as diarrhea, nausea and vomiting.
The thiazide, the combination partner of triamterene and amiloride, counteracts the increased potassium level:
While thiazides lead to an increased excretion of potassium, amiloride and triamterene reduce the loss of potassium - thus the two effects in the combination treatment balance each other out again and one can speak of a "positive side effect".
Side effects
Every drug has side effects - this is also the case with diuretics. The different groups of diuretics also have a different side effect profile, but some side effects can be found with all drugs.
In general, every drug carries the risk of developing hypersensitivity or allergy. This can lead to skin rashes, discomfort and even allergic shock. The aim of a diuretic is that more water is excreted from the body. In this way, water retention can be reduced and blood pressure can also be lowered. However, if the blood volume decreases due to the drainage, the risk of developing a thrombosis is increased.
The blood sugar is also lowered, this is to be observed above all with diabetics, as the medication may have to be changed in order to avoid the so-called hypoglycaemia, i.e. low blood sugar.In the course of dehydration, there is also an increase in uric acids in the blood. This can lead to a gout attack in patients with gout. Here, too, can be counteracted with drugs or nutritional technology.
All diuretics also have an effect on the potassium level in the blood - it is either lowered (thiazides and loop diuretics) or increased (potassium-sparing diuretics). How potassium levels affect our bodies is discussed separately in the next section. With all diuretics, it is also reported that some patients have gastrointestinal problems such as diarrhea, constipation, or nausea.
In the case of loop diuretics, such as furosemide, there is a particular change in the absorption and excretion of salts and electrolytes - this is what the urinating effect is ultimately based on. This leads to an increased excretion of calcium, magnesium and potassium. A long-term calcium deficiency can lead to osteoporosis, the fragility of bones. Some patients also report hearing disorders when taking loop diuretics - but these are usually completely reversed after stopping the drug.
The group of thiazides has specific side effects, in rare cases a change in the blood count. The doctor can determine this using a blood count. Erectile dysfunction occurs more frequently, i.e. an erectile dysfunction, which is also reversed after the drug is discontinued. Patients should not hesitate to consult their doctor in this case! Elderly patients in particular can experience a sharp drop in the sodium concentration in their blood. This can show up as sudden disorientation, confusion, or clouding over.
With the aldosterone antagonists there is the problem, especially with the spironolactone, that the drug can also act in other places in the body. So it can activate receptors for the sex hormones. The result in men can be gynecomastia (growth of breast tissue) or erectile dysfunction. In women, on the other hand, there may be a missed period (amenorrhea) or so-called hirsutism, ultimately a masculinization of the woman. It can also lead to voice changes such as hoarseness. The aldosterone antagonist eplerenone, on the other hand, does not bind as strongly to the sex hormone receptors and does not show these side effects.
If you notice any side effects, do not hesitate to consult your doctor. If necessary, he or she can dose or change the drug differently.
Potassium levels
Diuretics affect the level of potassium in the blood. Loop diuretics and thiazides lower the potassium level. If this falls into a critical range, a variety of side effects can occur. These include cardiac arrhythmias, dwindling muscle strength or over-acidification of the body (so-called metabolic acidosis).
Studies have also shown that low potassium levels reduce glucose tolerance and thus damage the sugar metabolism. Therefore, these diuretics are not recommended for young people and patients with diabetes.
The potassium-sparing diuretics, on the other hand, can lead to high potassium levels in the blood. This presents itself similar to a lack of potassium with muscle weakness and cardiac arrhythmias. Regular monitoring of the potassium level during diuretic treatment is recommended in any case. Potassium-sparing diuretics are also often combined with loop diuretics or thiazides in order to keep the potassium level stable.
What should be considered when stopping?
A diuretic is a dehydrating drug that can be given for various diseases. Some of these diseases are serious and the use of the diuretic is carefully considered by your doctor, so it is never advisable to stop taking a diuretic on your own without consultation.
For example, if the heart is weak, the increasing blood volume can put a lot of strain on the heart. If you discontinue a diuretic in consultation with your doctor, you should know that it can lead to a so-called "rebound effect". This means that after stopping the diuretic drug, the body may tend to store excessive amounts of water for a short time. This can lead to an increase in blood pressure or visible edema (water retention, often in the legs) for a few days. However, this effect is only short-term and after a few days an equilibrium should be restored. It is especially common after using loop diuretics.
Diuretics and gout
Gout is a condition that is characterized by increased levels of uric acids in the blood.
This uric acid can, for example, build up in joints and form crystals, which can lead to severe pain. When using diuretics, be sure to tell your doctor about any past attacks of gout, as the level of uric acids in the blood can increase as the body becomes dehydrated. They can then also prescribe a medication for gout (e.g. allopurinol) or increase the dosage. Depending on the reason for the diuretic administration, e.g. High blood pressure, he may also resort to other medication and avoid the use of diuretics.
Also read: Therapy of gout such as Diet for gout
Diuretics and doping
Diuretics have been banned doping drugs since the 1988 Olympic Games. They are called masking agents, which means that athletes can use these diuretic drugs to disguise another doping substance in the urine. As a result, other stimulating drugs may not be detected in the urine - this is then a deception and therefore prohibited. Also, diuretics are widely used in sports that have weight classes. For example, boxers can excrete a lot of water with the help of diuretics shortly before a fight and thus become lighter - this opens the way to a lower weight class. Something similar can be observed in equestrian sport, where the lower weight of the rider can have a positive effect on the horse's performance. Diuretics are also used in bodybuilding before competitions, as the loss of water can make the muscles appear even more defined. Athletes who use a diuretic due to a pre-existing condition such as heart disease are of course exempt from the ban as a masking agent. This must then be certified by a doctor.
Read more on this topic: doping
