Products
Diuretics are mainly administered in the form of tablets. In addition, injectables are also commercially available. Among the most commonly prescribed diuretics are loop diuretics (torasemide).
Effects
Diuretics (ATC C03) have diuretic and antihypertensive properties. Through various mechanisms, they cause increased excretion of water and electrolytes in the urine. They are active at the nephron of the kidney:
- Proximal tubule: inhibition of carbonic anhydrase (carbonic anhydrase inhibitors).
- Ascending branch of the loop of Henle: inhibition of Na+/K+/2Cl–-cotransporters (loop diuretics).
- Distal tubule: inhibition of reabsorption of sodium and chloride by inhibition of Na+/2Cl–-cotransporter (thiazides, thiazide-like diuretics).
- Distal tubule: inhibition of sodium reabsorption (potassium-sparing diuretics).
- Distal tubule and collecting tube: antagonism at the intracellular aldosterone receptor (aldosterone antagonists).
Osmotic diuretics enter the renal tubules by filtration and are not reabsorbed. They cause osmotic diuresis.
Indications
Typical indications are:
- Essential hypertension (high blood pressure).
- Edema of various causes, such as diseases of the heart, liver (ascites), kidney and burns.
- Heart failure
Abuse
Diuretics can be abused in competitive sports as so-called masking agents. They can mask the use of doping agents by reducing their urine concentration or promoting their excretion. Their use before or during competition is prohibited according to the doping list. Furthermore, diuretics can be misused in sports to lose weight rapidly. This is relevant for sports in which weight categories play a role.
Dosage
According to the SmPC. Diuretics are usually taken in the morning to avoid the need to go to the bathroom during the night.
Active ingredients
Osmotic diuretics:
- Mannitol
Carbonic anhydrase inhibitor:
- Acetazolamide (Diamox, Glaupax).
Loop diuretics:
- Bumetanide (Burinex, off label).
- Furosemide (Lasix, generic).
- Piretanide (combination drug).
- Torasemide (Torem, generic)
Thiazide diuretics:
- Hydrochlorothiazide (monopreparation: Esidrex, many combination preparations).
Thiazide-like diuretics:
- Chlortalidone (combination drugs).
- Indapamide (Fludex, Coversum Combi, generics).
- Metolazone (Metolazone Galepharm)
- Xipamide (Aquaphor, not commercially available in many countries).
Potassium-sparing diuretics:
- Amiloride (Moduretic, generic).
- Aldosterone antagonists: spironolactone (Aldactone, generic), canrenone (Soldactone), eplerenone (Inspra, generic).
- Triamterene (in many countries out of trade).
Herbal diuretics:
- Birch
- Caffeine drugs
- Goldenrod
- Roughy hackle
- Orthosiphonis
- Horsetail
- Juniper
- Asparagus
- Tea blends: Diuretic tea PH (Species diureticae).
Contraindications
Contraindications include (selection, depending on the active ingredient):
- Hypersensitivity
- Hypotension
- Hypovolemia
- Disturbances of the electrolyte balance
- Renal failure
- Dehydration
- Pregnancy and lactation (depending on the substance).
Full precautions can be found in the drug label.
Adverse effects
The most common potential adverse effects include disturbances in electrolyte balance (eg, sodium, potassium, chloride, bicarbonate, calcium, magnesium) and hypotension. Regarding potassium, diuretics can cause hypokalemia or hyperkalemia depending on the active ingredient. This increases the risk for the development of cardiac arrhythmias. Diuretics can lead to an increase in blood glucose levels, uric acid levels and blood lipid levels (hyperglycemia, hyperuricemia, hyperlipidemia).
