The drug torasemide belongs to the loop diuretics and is mainly used for drainage. Possible indications include water retention, hypertension, and heart failure.
What is torasemide?
Torasemide is a loop diuretic. This group of diuretic medications exerts its effects directly in the kidneys’ urinary system. Due to their fairly linear effect-concentration relationship, loop diuretics such as torasemide are classified as high-ceiling diuretics. Depending on fluid administration, a urine volume of up to 45 liters per day can be achieved with the help of the loop diuretic.
Pharmacologic action
The kidney filters metabolic end products from the blood and excretes them. To do this, it initially produces up to 200 liters of primary urine daily. This is concentrated in a complex system of so-called tubules, the loop of Henle, and collecting tubes. Water is reabsorbed, so that between one and one and a half liters of secondary urine remain. The ascending part of the loop of Henle is the site of action of torasemide. Here, up to 25 percent of the initially filtered sodium re-enters the blood. A transport protein is needed for the sodium to be reabsorbed. Torasemide inhibits this protein. The sodium can then no longer be reabsorbed. This also increases water excretion. At the same time, there is an increase in the so-called glomerular filtration rate. This means that the renal corpuscles filter and produce more urine.
Medical application and use
Loop diuretics such as torasemide are used mainly in the treatment of acute pulmonary edema. This is where fluid collects in the alveoli or lung tissue as a result of heart disease. The result is life-threatening breathing problems. Torasemide can help eliminate the excess fluid from the body. Water retention in other organs, such as the abdomen or extremities, is also treated with torasemide. Such edema can develop in the setting of heart, liver, or kidney failure and severely impair organ function. In acute renal failure, torasemide can help control water balance, at least for a time. Since the loop diuretic causes not only increased water but also electrolytes to be excreted, torasemide can also be used to treat hypercalcemia. In hypercalcemia, there is too much calcium in the blood. Typical causes are malignant tumors or diseases of the endocrine system. Loop diuretics also wash out potassium in addition to calcium. Another area of application is therefore hyperkalemia, which can occur, for example, in diseases of the kidneys or adrenal glands. In the past, torasemide was also used for forced excretion in cases of poisoning with bromide, fluoride and iodide, as well as in rhabdomyolysis, a dissolution of striated muscle fibers. However, to prevent disturbances in electrolyte balance, a simultaneous supply of sodium, water, and chloride is required.
Risks and side effects
Loop diuretics such as torasemide have high efficacy and therefore must be used cautiously. Especially in patients with disturbed electrolyte or acid-base balance, a close-meshed balancing of water balance and adequate substitution of electrolytes is essential. Due to increased excretion of electrolytes, torasemide should not be used in cases of sodium and potassium deficiency. Its use is also contraindicated in cases of complete urinary retention. Similarly, the drug must not be used during breastfeeding. If the use of the drug is vital, breastfeeding must be done beforehand. Long-term use may lead to so-called hypovolemia due to excessive dehydration. In hypovolemia, the circulating blood volume is reduced. This is manifested by symptoms such as dizziness, headache and hypotension. In severe cases, patients may become dehydrated. Increased excretion of potassium and protons can lead to hypokalemic acidosis. In rare cases, patients may also have decreased blood sodium levels. Hyperuricemia may further develop due to increased reabsorption of uric acid, which may lead to gout attacks. Some patients develop hearing loss in the high frequencies to complete deafness during treatment with torasemide.However, this effect usually occurs only during treatment, and permanent damage is very rare.
