DOES IN VIVO INCUBATION OF FUROSEMİDE WITH ALBUMIN INCREASE ITS NATRIURETIC AND DIURETIC EFFECTS IN PATIENTS WITH NEPHROTIC SYNDROME ?

It has been claimed that the diuretic action of furosemide (F) is decreased in patients with nephrotic syndrome (NS), because less F reaches renal tubules in hypoalbuminemia since F is bound tightly to albumin (A). It has been showed that F acts only after being bound to A in analbuminemic rats. It is advised to combine F with A in order to increase the diuretic effect, although there is not any controlled study in man.

We investigated the diuretic effect of furosemide-albumin (FA) complex incubated just before infusion and compared with the effect ofF alone, in the same patients. We selected 10 edematous patients with NS whose serum albumin is between 1,0 - 3,0 g/dl (mean 1,8 ± 1,0 g/dl) and serum creatinine less than 2 mg/dl (mean 0.7 ±0.1 mg/dl). They were maintained on bed rest and 40 mmol sodium diet, while all medications were stopped. The study consisted of 3 stages: Stage 1: 60 mg F in 50 ml of saline was infused in 15 minutes; Stage 2: 60 mg F incubated with 50 ml of 20% human albumin 10 minutes before infusion, then infused in 15 minutes; Stage 3: 60 mg F in 50 ml of saline was infused in 15 minutes (same as stage 1).

Between F and FA infusions, 1 to 3 days were left for stabilization of body weight. Urine volume (V) and natriuresis (UNa) during 6 hours after infusions were compared. The results are shown in the table.

UNa (nunol/st) V (ml/st) *ns Kontrol 1.1*0.3 39+5 F 17.7*2.4 196+21 FA 20.7+3.5 * 204+28*

Furosemide alone proved to have strongly diuretic and natriuretic effect. Previous incubation with albumin did not significantly increase the natriuretic effect of furosemide in patients with nephrotic edema.