From the Guidelines
Torsemide acts as a loop diuretic by inhibiting the reabsorption of sodium or chloride at the loop of Henle in the renal tubules.
Mechanism of Action
- The mechanism of action of torsemide is similar to other loop diuretics, such as bumetanide and furosemide, which increase sodium excretion up to 20% to 25% of the filtered load of sodium and enhance free water clearance 1.
- Torsemide and other loop diuretics maintain their efficacy unless renal function is severely impaired, making them the preferred diuretic agents for use in most patients with heart failure 1.
- The effects of torsemide on morbidity and mortality are not well established, but it has been shown to improve symptoms and exercise tolerance in patients with heart failure 1.
Key Points
- Torsemide is a loop diuretic that acts at the loop of Henle in the renal tubules.
- It increases sodium excretion and enhances free water clearance.
- It is effective in patients with heart failure, unless renal function is severely impaired.
- Its effects on morbidity and mortality are not well established, but it improves symptoms and exercise tolerance in patients with heart failure.
- Sex-related differences in the pharmacological treatment of heart failure may affect the efficacy and safety of torsemide, with women potentially experiencing more adverse effects and requiring different dosing regimens 1.
From the FDA Drug Label
Micropuncture studies in animals have shown that torsemide acts from within the lumen of the thick ascending portion of the loop of Henle, where it inhibits the Na+/K+/2Cl–-carrier system. Clinical pharmacology studies have confirmed this site of action in humans, and effects in other segments of the nephron have not been demonstrated Diuretic activity thus correlates better with the rate of drug excretion in the urine than with the concentration in the blood. Torsemide increases the urinary excretion of sodium, chloride, and water, but it does not significantly alter glomerular filtration rate, renal plasma flow, or acid-base balance.
The mechanism of action of Torsemide is the inhibition of the Na+/K+/2Cl–-carrier system in the thick ascending portion of the loop of Henle, leading to increased urinary excretion of sodium, chloride, and water 2.
From the Research
Mechanism of Action of Torsemide
The mechanism of action of torsemide involves inhibiting the sodium-potassium-chloride (Na+/K+/2Cl-) cotransporter in the thick ascending limb of the loop of Henle within the nephron 3. This inhibition leads to the promotion of rapid and marked excretion of water, sodium, and chloride 4. Torsemide acts from the luminal side of the cell, similar to furosemide, and is at least twice as potent as furosemide on a weight-for-weight basis 4.
Key Aspects of Torsemide's Mechanism
- Inhibition of Na+/K+/2Cl- cotransport in the thick ascending limb of the loop of Henle 3, 5
- Promotion of diuresis, natriuresis, and other effects 4, 6
- High bioavailability and relatively long half-life 5, 6
- Highly protein bound 6
Clinical Implications
Torsemide's mechanism of action makes it an effective diuretic for the treatment of conditions such as heart failure, cirrhosis, chronic kidney disease, and hypertension 3, 4, 5, 7, 6. Its ability to promote diuresis and lower blood pressure makes it a useful alternative to other diuretics, such as furosemide 4, 5. However, further research is necessary to fully understand its long-term effects and to establish optimal dosing strategies 7.