[Renal function and water and electrolyte balance during i.v. infusion of fenoterol (Partusisten) (author's transl)].

Renal function and electrolyte transport during i.v. Fenoterol treatment (0,021 +/- 0,008 mug/kg/min) were measured in 10 healthy, nonpregnant patients by means of clearance studies utilizing water diuresis. Three 10-min control periods were followed by 9 experimental periods conducted over altogether 90 min., during which the following parameters were measured: diuresis (V), glomerular filtrate (CIn), renal plasma flow (CPAH), urinary and plasma osmolality plasma levels of Na, K and Cl, and their urinary excretion. During Fenoterol infusion, diuresis fell on average from 13.1 in the controls to 6,0 ml/min (p less than 0,01), with a concurrent rise of U/P osmol from 0,215 to 0,984 (p less than 0,01). CIn and CPAH did not change significantly, nor were there any fluctuations in plasma Na and Cl and the respective urinary excretions. The plasma potassium concentration decreased from 3,7 in the controls to 2,7 mEq/l (p less than 0,01) and was associated with a simultaneous fall of the potassium excretion from 0,060 to 0,024 mEq/l (p less than 0,01). The demonstrated antidiuretic action of Fenoterol would appear to be due, as in the case of other betamimetic drugs, to endogenous release of ADH. As shown by our experiments, the fall in plasma K is not attributable to renal factors but may be explained by displacement of K into the cell.