They increase the elimination of fluids through the urine (diuresis): they are mainly used in hypertension and heart failure.

What are they

Diuretics are drugs that increase the elimination of fluids through the urine (diuresis). They are mainly used in hypertension and heart failure.

In the first case, they allow to reduce the volume of blood and the pressure that this exerts on the vascular walls, thus obtaining a reduction in pressure values.

In the second case, they allow the tissues to eliminate fluid stagnation (edema) due to an inefficient thrust of the heart.

Diuretics act by modifying the salt balance in the kidney: the concentration of sodium and other salts in the urine is increased with a consequent recall of water from the blood.

They can be used individually or in combination. The increased diuresis resulting from the intake of diuretics causes a more frequent need to urinate.

There are several categories of diuretics with different action.

Diuretic class Active ingredients
Loop diuretics Furosemide, bumetanide, ethacrynic acid, pyrethanide
Thiazide diuretics Chlorthiazide, hydrochlorthiazide, chlorthalidone, metolazone, kinetazone
Carbonic anhydrase inhibitors Acetazolamide, diclofenamide
Potassium sparers Spironolactone, triamterene, amiloride
Osmotic diuretics mannitol

Loop diuretics

They are named after their site of action inside the kidney. They are drugs with very strong diuretic activity, used in particular in hypertension.

Because they act in a part of the kidney (the loop of the renal tubule) that controls the reabsorption of sodium and calcium, they can lead to a loss of calcium in the body after prolonged treatment.

To this class belong furosemide, bumetanide, ethacrynic acid and pyrethanide.

Thiazide diuretics

The action of these molecules can vary up to 48 hours. They are mainly used in hypertension.

Thiazide drugs include chlorthiazide, hydrochlorthiazide, chlorthalidone, metolazone, kinetazone, also used in combination with other diuretics.

They can cause a loss of potassium in the urine.

Carbonic anhydrase inhibitors

They increase the concentration of certain salts in the urine by blocking the action of a renal enzyme, carbonic anhydrase.

To this class belong acetazolamide and diclofenamide, used mainly in subjects with edema, but also in those suffering from glaucoma (ocular pathology characterized by increased fluid inside the eye).

Potassium sparers

Normally they are not used in monotherapy but in combination with thiazide diuretics, as they have a modest diuretic activity but the ability to block potassium secretion in the urine.

The potassium retention induced by drugs of this class is exploited to reduce the loss of this element, one of the most important side effects of thiazide diuretics.

Among the potassium sparers are spironolactone, triamterene and amiloride.

Osmotic diuretics

To this class of compounds belong substances that, after renal filtration, pass into the urine dragging with them a large amount of liquids as they have a particular affinity for water.

An example of an osmotic diuretic is mannitol, used in neurology to reduce cerebral edema and during certain clinical conditions or surgery to prevent acute renal failure, i.e. a drastic reduction in kidney function.

Joycelyn Elders is the author and creator of EmpowerEssence, a health and wellness blog. Elders is a respected public health advocate and pediatrician dedicated to promoting general health and well-being.

The blog covers a wide range of topics related to health and wellness, with articles organized into several categories.

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