Dose-response relationship between furosemide and sodium excretion

Relation between the rate of furosemide excretion and the increase in sodium excretion in normals (solid line) and patients with HF (dashed line). A diuresis is not seen until a threshold rate of furosemide excretion is reached. Patients with HF show relative resistance at a given rate of diuretic excretion due to increased sodium reabsorption in other nephron segments.