Mechanism of Action of Furosemide

Furosemide, a loop diuretic, provides rapid relief of dyspnea and pulmonary edema in congestive heart failure (CHF), acting within minutes despite its diuretic effects taking longer to manifest. The immediate improvement is attributed to a non-diuretic mechanism that involves a decrease in left ventricular filling pressures, leading to enhanced venous capacitance. This venodilation occurs as furosemide stimulates the release of prostaglandins, which facilitate vessel dilation without initially causing significant urine production. Therefore, the quick clinical benefits observed upon administration can be misleading if interpreted solely through the lens of diuresis, highlighting the need for clinicians to understand the drug's broader physiological effects.