From the Guidelines
Torsemide is generally considered better than furosemide (Lasix) for the treatment of heart failure due to its better bioavailability, longer half-life, and increased potency, as evidenced by the 2022 AHA/ACC/HFSA guideline for the management of heart failure 1. The key differences between torsemide and furosemide lie in their pharmacokinetic properties. Torsemide has a bioavailability of 80-100%, compared to 50-60% for furosemide, allowing for more consistent absorption regardless of food intake or gastrointestinal issues. Additionally, torsemide has a longer half-life of 12-16 hours, enabling once-daily dosing and a more sustained diuretic effect, whereas furosemide has a half-life of 6-8 hours 1. Some of the benefits of torsemide include:
- Better bioavailability, resulting in more consistent absorption
- Longer half-life, allowing for once-daily dosing and a more sustained diuretic effect
- Increased potency, with 10-20mg of torsemide equivalent to 40-80mg of furosemide
- Less potassium loss and potential anti-aldosterone and anti-fibrotic effects that could benefit heart failure patients However, it is essential to consider the potential drawbacks, such as the generally higher cost of torsemide compared to generic furosemide, which may influence medication choice depending on insurance coverage and patient finances. In clinical practice, when switching from furosemide to torsemide, the typical conversion is 40mg furosemide to 10-20mg torsemide, as suggested by the guideline 1. It is crucial to monitor patients closely during diuretic therapy, particularly during the initial weeks of treatment, to avoid potential complications such as severe hyponatremia, acute kidney injury, or worsening hepatic encephalopathy, as recommended by the EASL clinical practice guidelines for the management of patients with decompensated cirrhosis 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Comparison of Torsemide and Furosemide
- Torsemide has been shown to have less inter- and intra-individual variation in bioavailability and a longer duration of action compared with furosemide 2.
- Studies have demonstrated that torsemide significantly reduces heart failure (HF) and cardiovascular (CV)-related hospital readmissions in systolic HF compared to furosemide 2, 3.
- Torsemide is associated with a trend in reducing all-cause mortality compared to furosemide 2.
- In patients with heart failure, torsemide has been shown to decrease mortality, hospitalizations, and improve New York Heart Association functional classifications compared to furosemide 3.
- The safety profile of torsemide is more favorable, with a reduced risk of hypokalemia compared to furosemide 4.
Pharmacological Properties
- Torsemide has more favorable pharmacokinetic profiles compared to furosemide, with a longer duration of action and less variation in bioavailability 2, 3.
- Torsemide has been shown to increase natriuresis and total volume diuresed compared to furosemide in patients with cirrhosis 3.
- In patients with pulmonary hypertension, torsemide has been shown to improve central venous pressure, capillary wedge pressure, and stroke volume compared to furosemide 3.
Clinical Outcomes
- Torsemide has been shown to improve clinical outcomes, including body weight, presence of edema, signs and symptoms of HF, and electrocardiogram and echocardiographic evaluation compared to furosemide 5.
- The change in procollagen type I carboxyterminal peptide (PICP) serum levels between baseline and final visit was used as the primary efficacy end point in a randomized controlled study comparing furosemide and torsemide 5.
- Secondary efficacy variables included parameters related to the clinical course of HF, such as amino-terminal pro brain-type natriuretic peptide (NT-proBNP) serum levels, systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate, and renal function 5.