Torasemide is a diuretic medication used to treat fluid overload due to heart failure, kidney and liver disease, and high blood pressure. It belongs to the group of loop duiretics. However, it for the treatment of high blood pressure not first choice. Torasemide is taken by mouth or by injection into a vein.
Torasemide belongs to the loop diuretics and thus acts by increasing the sodium concentration in the medullary thick ascending loop of Henle by inhibiting the Na+/K+/Cl pump at the luminal cell membrane surface. As a result, more water is reabsorbed from the blood and excreted in the downstream portions of the nephron. The loss of volume lowers the blood pressure in the body.
Torasemide is the diuretic with the highest oral bioavailability even in advanced stages of chronic kidney disease. This is usually over 80%, regardless of the patient's condition. Torasemide is highly bound to plasma proteins. The bound portion usually accounts for over 99%. Torasemide is metabolized in the liver after which only 20% of the dose remains unchanged. Torasemide is metabolized via hepatic CYP2C8 and CYP2C9 mainly to 5 metabolites. Most of the given dose is excreted in feces (80%).
Interactions may occur with drugs that are metabolized by the same enzymes ( CYP2C8 and CYP2C9) or with drugs that induce these enzymes.
Loop diuretics, including torsemide, may decrease total body thiamine levels, especially in individuals with poor thiamine intake. This thiamine deficiency can worsen heart failure. It is therefore reasonable to either administer additional thiamine supplements or monitor blood thiamine levels in individuals treated with chronic loop diuretics.
Common side effects include headache, increased urination, diarrhea, cough, and dizziness. Other side effects may include hearing loss and low blood potassium and magnesium. Torasemide is a sulfonamide and therefore may cause allergic reactions. There may be uric acid retention, which promotes a gout attack. Furthermore, a decreased glucose tolerance occurs.
Use during pregnancy or lactation is not recommended.
LD50 (rat, oral): > 5000 mg-kg-1
| ATC Code | C03CA04 |
| Formula | C16H20N4O3S |
| Molar Mass (g·mol−1) | 348,42 |
| Physical State | solid |
| Melting Point (°C) | 163–164 |
| PKS Value | 6,44 |
| CAS Number | 56211-40-6 |
| PUB Number | 41781 |
| Drugbank ID | DB00214 |
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