What is the best diuretic to start with in the management of heart failure?

Best Diuretic to Start with in Heart Failure

Start with a loop diuretic—furosemide is the most commonly used first-line agent, though torsemide may offer advantages in bioavailability and duration of action. 1

Loop Diuretics as First-Line Therapy

Loop diuretics are the recommended first-line diuretic class for heart failure management. 2 The ACC/AHA guidelines consistently identify loop diuretics as essential for controlling fluid retention in heart failure, as they are the only drugs that can adequately manage the volume overload characteristic of this condition. 1

Furosemide vs. Torsemide

Furosemide remains the most commonly prescribed loop diuretic, with typical starting doses of 20-40 mg once or twice daily, titrated up to a maximum of 600 mg daily. 1 However, the guidelines acknowledge that some patients respond more favorably to alternative loop diuretics. 1

Torsemide offers pharmacologic advantages over furosemide:

• Superior oral bioavailability and absorption, particularly important as heart failure progresses and bowel edema develops 1
• Longer duration of action (12-16 hours vs. 6-8 hours for furosemide) 1
• Starting dose of 10-20 mg once daily, with maximum doses up to 200 mg 1, 3

Recent evidence favors torsemide for clinical outcomes: A 2024 meta-analysis of randomized controlled trials demonstrated that torsemide significantly reduced hospitalizations for heart failure (RR 0.60, p=0.002) and cardiovascular hospitalizations (RR 0.72, p=0.0009) compared to furosemide, while also improving left ventricular ejection fraction by 4.51%. 4 Importantly, there was no difference in all-cause mortality or overall hospitalizations between the two agents. 4

Practical Initiation Strategy

Begin with low doses and titrate upward based on response:

• Start furosemide 20-40 mg once or twice daily OR torsemide 10-20 mg once daily 1
• Increase dose until urine output increases and weight decreases by 0.5-1.0 kg daily 1
• Goal is complete elimination of clinical fluid retention (no jugular venous distension, no peripheral edema) 1

Always combine loop diuretics with:

• ACE inhibitor or ARB 1
• Beta-blocker 1
• Moderate dietary sodium restriction (3-4 g daily) 1

Critical Pitfalls to Avoid

Underdosing is more dangerous than overdosing in the acute setting. Excessive concern about hypotension and azotemia leads to underutilization of diuretics and refractory edema, which perpetuates symptoms and compromises the efficacy and safety of other heart failure medications. 1 Continue diuresis until fluid retention is eliminated, even if mild-to-moderate decreases in blood pressure or renal function occur, as long as the patient remains asymptomatic. 1

Never use diuretics as monotherapy. Even when successful at controlling symptoms, diuretics alone cannot maintain clinical stability long-term and must be combined with neurohormonal blockade (ACE inhibitor/ARB and beta-blocker). 1

When to Escalate Beyond Initial Loop Diuretic

If inadequate response to maximized loop diuretic therapy after 24-48 hours:

• Consider switching from furosemide to torsemide for better bioavailability 1
• Add a thiazide diuretic (metolazone 2.5-10 mg or hydrochlorothiazide 25-100 mg) for sequential nephron blockade 1, 2
• Consider continuous IV infusion rather than bolus dosing 5

Monitor for diuretic resistance causes:

• High sodium intake 2
• NSAID use 2
• Significant renal impairment 2
• Bowel edema impairing absorption 1