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The following is a summary of “Mechanistic Differences between Torsemide and Furosemide,” published in the August 2024 issue of Nephrology by Rao et al.

Torsemide is thought to offer benefits over furosemide in treating heart failure (HF), but it is unclear if it improves clinical outcomes.

Researchers conducted a prospective study named Torsemide Comparison with Furosemide for Management of Heart Failure (TRANSFORM-HF) and tested if torsemide led to better results than furosemide in managing HF. 

They conducted a multicenter mechanistic substudy of patients with HF called TRANSFORM-Mechanism, where patients with HF were randomly assigned to take either oral furosemide or torsemide. Drug-related parameters (pharmacokinetic and pharmacodynamic) were also assessed at the start and after 30 days.

The results showed that the TRANSFORM-Mechanism enrolled 88 participants. Torsemide delivered less kidney bioavailability compared to furosemide (median 17.1% [IQR 12.3-23.5%] vs. 24.8% [16.6-34.1%], P<0.001) and had shorter drug delivery and natriuresis duration (P≤0.004). Despite similar doses to TRANSFORM-HF, torsemide caused more natriuresis (P<0.001) and required a 4:1 dose equivalence for similar effects. Higher torsemide doses led to mild kidney function changes and increased renin, aldosterone, and norepinephrine (P<0.05), but plasma volume and body weight showed no improvement (P=0.52 and P=0.89). 

Investigators concluded that torsemide didn’t offer clear benefits over furosemide. The increased natriuresis from higher doses of torsemide was balanced out by more neurohormonal activation and kidney issues.

Source: journals.lww.com/jasn/abstract/9900/mechanistic_differences_between_torsemide_and.409.aspx