Addition of indapamide to frusemide increases natriuresis and creatinine clearance, but not diuresis, in fluid overloaded ICU patients

Background: Fluid and sodium overload are a common problem in critically ill patients. Frusemide may result in diuresis in excess of natriuresis. The addition of indapamide may achieve a greater natriuresis, and also circumvent some of the problems associated with frusemide. The objective of this study was to examine the effect of adding indapamide to frusemide on diuresis, natriuresis, creatinine clearance and serum electrolytes. Methods: Fluid overloaded ICU patients were randomised to either intravenous frusemide (Group F) or intravenous frusemide and enteral indapamide (Group F + I). Comprehensive exclusion criteria were applied to address confounders. 24 hour urine was analysed for electrolytes and creatinine. Serum electrolytes were measured before and 24 hours after administration of diuretics. Results: Forty patients (20 in each group) were included in the study. The groups were similar in their baseline characteristics. Over the 24 h study period, patients in Group F + I, had a larger natriuresis (P = 0.01), chloride loss (P = 0.01) and kaliuresis (P = 0.047). Patients in Group F + I also had a greater 24 hour urinary creatinine clearance (P = 0.01). The 24 hour urine volume and fluid balance was similar between the groups. Patients in Group F had an increase in serum sodium (P = 0.04), while patients in Group F + I had a decrease in both serum chloride (P = 0.01) and peripheral oedema (P < 0.001) during the study duration. Conclusion: In fluid overloaded ICU patients, addition of indapamide to frusemide led to a greater natriuresis and creatinine clearance. Such a strategy might be utilised in optimising sodium balance in ICU patients.