The influence of age on renal and extrarenal effects of frusemide.

Abstract

The effect of frusemide 80 mg i.v. was compared during 24 h in 10 young and eight elderly healthy male volunteers following a 24 h control period in the ward. During the 30 min following the injection the increments in excretion of urine, sodium, potassium and frusemide were significantly smaller in the elderly. The 24 h increase in sodium excretion was significantly larger in the 0 young and eight elderly healthy male volunteers following a 24 h control period in the ward. During the 30 min following the injection the increments in excretion of urine, sodium, potassium and frusemide were significantly smaller in the elderly. The 24 h increase in sodium excretion was significantly larger in the 0 young and eight elderly healthy male volunteers following a 24 h control period in the ward. During the 30 min following the injection the increments in excretion of urine, sodium, potassium and frusemide were significantly smaller in the elderly. The 24 h increase in sodium excretion was significantly larger in the elderly. The endogenous 24 h creatinine clearance was reduced by 12% (P less than 0.01) in both age groups. The frusemide induced changes in the 8 h serum concentration curves for albumin differed significantly between the two groups (analysis of variance, P less than 0.01). The drug induced increase in albumin concentration became significant in the young 5 min after the injection. In the elderly it took more than 15 min before the increase in serum albumin reached significance. The average maximal increase in albumin concentration was 14.3% in the young and 9.7% in the elderly (P less than 0.05). No difference was seen between the two age groups in the significant frusemide induced increases in the 24 h albumin excretion but in the elderly a significantly larger decrease in the 24 h excretion of beta 2-microglobulin was observed (P less than 0.05). No significant age difference was observed in the initial significant increases in diastolic blood pressure observed in both age groups or between the later changes in systolic blood pressure which was significantly reduced in the young only. The slower haemoconcentration response in the elderly seemed associated with the slower secretion rate of frusemide to the tubular lumen. We found no evidence of an age related difference in tubular cell response to frusemide. It is emphasized that a maximal initial frusemide response in the elderly, in contrast to what was found in the young, probably was not achieved by the 80 mg i.v.