The short-term effect of intravenously given furosemide on electrolyte and water excretion was evaluated in 11 adults with severe renal insufficiency and edema. Furosemide administration induced an increase in urine flow and sodium excretion in each patient, but the observed diureses were sufficient to afford practical benefit only in patients whose glomerular filtration rates were 5 ml/min or greater. The magnitude of the observed diuresis appeared directly related to the degree of filtration rate reduction, but an obvious relationship between filtration rate and fractional changes of water and electrolyte excretion was not observed. An increase in urine potassium excretion usually occurred and appeared to be a function of increased urine flow rather than increased concentration of potassium in urine.
Gregory LF, Durrett RR, Robinson RR, Clapp JR. The Short-Term Effect of Furosemide on Electrolyte and Water Excretion in Patients With Severe Renal Disease. Arch Intern Med. 1970;125(1):69-74. doi:10.1001/archinte.1970.00310010071005