What is the AHA guideline for using Lasix (furosemide) alone vs Lasix (furosemide) and Metalazone (metolazone) in congestive heart failure (CHF) exacerbation?

From the Guidelines

According to the 2022 AHA guideline, furosemide (Lasix) alone is typically recommended as the first-line therapy for fluid overload in CHF exacerbation, starting with IV doses of 20-40mg, and combination therapy with furosemide and metolazone may be considered for patients with diuretic resistance or severe volume overload. The guideline suggests that metolazone can be added at doses of 2.5-20mg orally, as seen in the table of commonly used oral diuretics in the treatment of congestion for chronic HF 1. This combination works by blocking sodium reabsorption at different sites in the nephron, resulting in enhanced diuresis.

When using combination therapy, close monitoring of electrolytes, particularly potassium and magnesium, is essential as the risk of electrolyte abnormalities increases, and renal function should also be monitored closely as aggressive diuresis can lead to acute kidney injury. The combination therapy should be used for the shortest duration necessary to achieve euvolemia, after which patients should be transitioned back to their maintenance diuretic regimen.

Some key points to consider when using diuretics in CHF exacerbation include:

• Diuretic resistance can be overcome by escalating the loop diuretic dose, intravenous administration of diuretics, or combination of different diuretic classes 1
• Patients may become unresponsive to high doses of diuretic drugs if they consume large amounts of dietary sodium, are taking agents that can block the effects of diuretics, or have significant impairment of renal function or perfusion 1
• The use of inappropriately low doses of diuretics will result in fluid retention, while the use of inappropriately high doses of diuretics will lead to volume contraction, which can increase the risk of hypotension and renal insufficiency 1

Overall, the choice of diuretic therapy in CHF exacerbation should be individualized based on the patient's specific needs and clinical status, and guided by the most recent and highest quality evidence, such as the 2022 AHA guideline 1.

From the Research

AHA Guideline for Lasix Alone vs Lasix and Metalazone in CHF Exacerbation

• The American Heart Association (AHA) guideline for the treatment of congestive heart failure (CHF) exacerbation recommends the use of diuretics, such as furosemide (Lasix), as first-line therapy 2.
• However, there is limited evidence on the specific use of Lasix alone vs Lasix and Metalazone (metolazone) in CHF exacerbation.
• Studies have shown that the combination of furosemide and metolazone can induce greater natriuresis, urinary output, and weight loss than furosemide alone in patients with severe CHF 3, 4.
• One study found that the addition of metolazone to furosemide resulted in a significant increase in diuresis and natriuresis in patients with refractory CHF 4.
• Another study reported that the combination of furosemide and metolazone was effective in treating patients with severe CHF, but also noted the potential for severe electrolyte disturbances, such as hyponatremia and hypokalemia 5.
• The use of low-dose furosemide (20 mg) has been shown to be effective in producing a significant diuretic and natriuretic effect in CHF patients, and may be a viable option for patients who do not respond to higher doses 6.

Key Findings

• The combination of furosemide and metolazone may be more effective than furosemide alone in treating CHF exacerbation.
• The use of metolazone in combination with furosemide requires careful monitoring of electrolyte levels due to the potential for severe disturbances.
• Low-dose furosemide may be a viable option for patients who do not respond to higher doses.

Studies

• 3: Combination of furosemide and metolazone in the treatment of severe congestive heart failure.
• 4: Metolazone in the treatment of refractory heart insufficiency.
• 2: Effects of high-dose furosemide and small-volume hypertonic saline solution infusion in comparison with a high dose of furosemide as a bolus, in refractory congestive heart failure.
• 5: Severe electrolyte disturbances associated with metolazone and furosemide.
• 6: Diuretic and clinical effects of low-dose furosemide in congestive heart failure patients.