#4949 COMBINED ORAL DIURETICS: A BETTER ALTERNATIVE FOR NEPHROTIC EDEMA THAN INTRAVENOUS FUROSEMIDE?
Authors: Fratila Valentina-Georgiana , Achim Camelia , Balanica Sonia , Bobeica Raluca , Lupusoru Gabriela Elena , Micu Georgia , Zilisteanu Diana-Silvia , Mocanu Valentin , Ismail Gener 
Published: June 2023

Abstract

Background and Aims
Edema is a serious complication of nephrotic syndrome and is the main reason why patients usually address to a doctor. There is no guideline on managing nephrotic edema. Besides non pharmacological interventions such as sodium and water restrictions, most doctors would choose high doses of intravenous furosemide as the first option, but still many patients fail to properly decrease their volume overload, as they become diuretic resistant. Amiloride, an ENaC mediated diuretic, is an optimistic management option, especially when used with other diuretics. The aim of the present study was to assess the non inferiority of the combined oral diuretics furosemide and the fixed combination of hydrochlorothiazide/amiloride diuretics with intravenous furosemide in diuretic resistant nephrotic edema.

Method
We conducted a prospective randomized trial in 22 patients with diuretic resistant nephrotic edema. Based on a computer-generated randomization we assigned patients to receive either intravenous furosemide (40 mg bolus and then continuous administration of 5 mg/h) or oral furosemide (40 mg/day) and hydrochlorothiazide/amiloride (50/5 mg/day). Clinical and laboratory measurements were performed daily, for five days (body weight, urinary output, blood pressure and hydration status by bioimpedance twice, creatinine, urea, albumin, hematocrit, Na, K, Ca, Mg, bicarbonate, pH). The primary outcome was weight and hydration status change from baseline to day 5. Secondary outcomes were safety outcomes (low blood pressure, severe dyselectrolytemia, acute kidney injury or aggravated hypervolemia).

Results
The patients were equally distributed between the two groups. Mean age was 47,77±15,97 (54,5% females and 45,5% males). Half of the patients had membranous nephropathy (45,5%), followed by minimal change disease (22,7%) and lupus nephritis (9,1%). 86,4% of patients had their first episode of nephrotic edema. The mean weight decrease was of significantly larger magnitude in the combined oral diuretics group compared with the intravenous furosemide group (-7,97±2,83 [SD] vs -4,5±2,6 [SD] kg; p = 0,018). Although the increase in 24-hour urine sodium excretion was higher in combined oral diuretics as compared to intravenous furosemide group, this increment was not statistically significant different (26,79±33,48 [SD] vs 16,04±42,81 mmol/24 h [SD]; p = 0,5). Mean values for changes in systolic and diastolic BP, 24-hour urine volume, hydration status measured by bioimpedance were not significantly different between the two groups. A total of 5 patients could not be followed through, 4 in the intravenous furosemide (two patients experienced low blood, one patient had no response to iv furosemide and one patient suffered from insomnia due to iv pump) and one patient in the oral combination of diuretics group had severe hyperkalemia (&gt;6,5 mmol/l).

Conclusion
Combined oral diuretics with furosemide, amiloride and hydrochlorothiazide is more effective and safer than intravenous furosemide for the treatment of refractory nephrotic edema. These results make amiloride a promising diuretic and further trials with larger sample sizes and longer follow-up are needed in this regard.