Furosemide Therapy in Patients with Cardiovascular or Renal Disease

Introduction to Furosemide Mechanism and Therapeutic Effects

The European Society of Cardiology recommends furosemide as a first-line diuretic for patients with acute heart failure and signs of fluid overload, with an initial dose of at least the previous oral dose used at home 1
Furosemide inhibits the Na-K-2Cl cotransporter (NKCC2) in the ascending limb of the loop of Henle, increasing renal excretion of sodium and water, and produces an additional vasodilatory effect that decreases right atrial pressure and pulmonary capillary pressure within 5-30 minutes after intravenous administration 1, 2

For acute heart failure, the American Heart Association suggests furosemide intravenously as the first-line diuretic, with a dose of 20-40 mg IV for patients without previous diuretic use, and higher doses for those with chronic diuretic use 1
In patients with cirrhosis and ascites, the European Association for the Study of the Liver recommends starting with spironolactone 100 mg and furosemide 40 mg orally in a single morning dose, maintaining a 100:40 mg ratio, and increasing every 3-5 days if weight loss and natriuresis are inadequate 3

The European Society of Cardiology advises monitoring serum electrolytes, CO2, creatinine, and BUN frequently during the first months of therapy and periodically thereafter, and reevaluating volume status in 1-4 hours depending on the response to diuretic therapy 3, 4
Furosemide is contraindicated in patients with anuria, severe hyponatremia (sodium <120-125 mmol/L), hypovolemic states, symptomatic hypotension, or persistent and overt hepatic encephalopathy 1, 3, 4, 5

In pediatric patients, furosemide may precipitate nephrocalcinosis/nephrolithiasis, especially in preterm infants, and requires monitoring of renal function and ultrasound of the kidneys 6
For geriatric patients, dose selection should be cautious, generally starting at the lower end of the dosing range, due to the increased risk of toxic reactions and decreased renal function 5

The European Society of Cardiology recommends a dual blockade of the nephron with loop diuretics plus thiazides or natriuretic doses of mineralocorticoid receptor antagonists, requiring careful monitoring to avoid hypokalemia, renal dysfunction, and hypovolemia 1
Increasing the dose and/or frequency of administration, using intravenous administration, and considering combination with dopamine or dobutamine may also be effective in managing diuretic resistance 2