Diuretics (Thiazides, thiazide-like and others commonly known as "Water Pills")

Mechanism of Action High Blood Pressure Medication Diuretics

Diuretics (Water Pills): Effect

The diuretics commonly referred to as "water pills" (here thiazides and thiazide-like) such as hydrochlorothiazide (HCT), indapamide, xipamide, and so on, increase the excretion of water and salt through the kidneys as dehydrating agents. When combined with other antihypertensive medications, they can enhance their effects. Diuretics lower blood pressure not only by reducing the fluid volume in the body but also in the long term, as they likely decrease the responsiveness of the vasoconstricting receptors.

As a first choice, a thiazide diuretic is often used: hydrochlorothiazide (HCT).

HCT is frequently used in multiple combination therapies and is available in many different combination preparations. The most well-known active ingredient in this group is hydrochlorothiazide. A thiazide combination preparation is often the first choice when initiating a pharmacological hypertension therapy.

At the end of 2018, there was information sent to doctors (black triangle letter) about a possible increased risk of skin cancer from HCT. This is based on data from the Danish Cancer Registry. However, the German Society of Cardiology warns against discontinuing it on one's own. Always consult your doctor.

However, there are also other diuretic substances that can be used.

For example, loop diuretics - mostly sulfonamide derivatives like furosemide or torasemide. Loop diuretics act in the loop of Henle in the kidney (hence the name) and are highly effective diuretic medications.

Through the aforementioned groups of diuretics, there can also be an increased excretion of minerals in addition to the increased excretion of water and salt.

In contrast, potassium-sparing diuretics such as representatives from the group of aldosterone antagonists (see extra article Mineralocorticoid Receptor Antagonists = MRA) e.g. spironolactone and from the group of ENaC inhibitors e.g. amiloride.

By the way:

Those who think they can achieve a similar effect as with a water pill simply by reducing their fluid intake are mistaken and may even harm themselves. The kidneys need a certain amount of fluid every day to function properly and to dispose of metabolic waste products. If these remain in the body due to insufficient fluid intake, kidney diseases can result.

Diuretics: Side Effects

Many patients find the frequent urge to urinate unpleasant. There can be low levels of sodium and potassium in the blood. This can manifest as fatigue, muscle cramps, constipation, or heart rhythm disturbances. Additionally, diuretics can increase fat and sugar levels in the blood. Nevertheless, the overall effect is heart-protective. Due to the "thickening" of the blood, thrombosis or varicose veins can occur. Under diuretics, patients with elevated uric acid levels may experience more frequent gout attacks. Recent studies suggest a slightly increased risk of skin cancer under therapy with thiazides.

Please read your package leaflet for completeness.

Diuretics (Thiazides and thiazide-like) Active Ingredients:

Bemetizide, bendroflumethiazide, clopamide, chlortalidone, hydrochlorothiazide (HCT), indapamide, mefruside, xipamide
Diuretics (Thiazides/thiazide-like and loop diuretics)

Examples of Active Ingredients and Approved Medicinal Substances:

Diuretics, primarily in combination preparations

Sources:

By Sabine Croci. This article is medically reviewed. Last updated (03/2024).
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