In 8 patients with a slight restriction of the renal function (serum
creatinine 150-300 mumol/l), 10 patients with a severe restriction of the renal function (serum
creatinine greater than 300-1,200 mumol/l) and in 10 control persons with intact renal function on 2 subsequent days after 40 and 80 mg
furosemide the pharmacokinetic data were calculated intravenously from the course of the serum concentration and the renale excretion as well as pharmacodynamic parameters. In comparison to the control persons in patients with
creatinine values of more than 200 mumol/l still 4 hours after
intravenous injection furosemide could be proved in the serum. According to this the excretion of the unchanged
furosemide was clearly decreased in the 24-hour-urine. In decreased renal clearance of
furosemide the elimination half-life period was prolonged. In all three groups of patients the
diuretic effect of
furosemide was very distinctly marked in the first four hours after injection of 40 mg, a doubling of the dose did not increase this effect. Only in the first four hours also an increased excretion of
sodium, chloride and
calcium occurred; in the 24-hour-collection period no differences between the three groups were the result. The excretion of
creatinine and
urea-N in the urine was not influenced by
furosemide. Thus also in the
chronic renal insufficiency there is the indication of the
furosemide therapy only then, when the extracellular space or the intravasal volume are enlarged. As individual dose 40 mg are recommended intravenously.