[Furosemide--pharmacokinetics in geriatric patients with multimorbidity]

20 geriatric patients with multiple diseases were administered a single intravenous dose of 40 mg furosemide. Furosemide plasma and urine concentrations were measured using a thin-layer chromatography method (25) and were fitted to an open 2-compartment model. Furosemide half-life was prolonged twofold in the elderly patients compared with a control group of younger adults. In the same way renal clearance and total clearance were markedly reduced in the geriatric group. The nonrenal clearance and the volume of distribution (beta) were not significantly altered. There were many significant correlations between clinical and biochemical data and pharmacokinetic parameters, especially between blood pressure and the area under the curve (AUC 0-infinity), total clearance and nonrenal clearance of furosemide. Our data suggest a special function of alpha-2-globulins in binding of furosemide. Renal function (i.e. creatinine clearance) was shown to be an important parameter for estimating the elimination rate of furosemide.