ACETAZOLAMIDE-INDUCED CHANGES IN TOTAL BODY WATER AND EXTRACELLULAR FLUID AS ASSESSED BY BIOELECTRICAL IMPEDANCE

Abstract

Acetazolamide, a mild diuretic, is frequently prescribed in the prevention or amelioration of acute mountain sickness. The purpose of this study was to determine if the expected small and rapid changes in total body water (TBW) and extracellular fluid (ECF) during drug treatment could be assessed accurately using bioelectrical impedance analysis (BIA). For four consecutive weeks at sea level, TBW, ECF, and body weight (BW) were determined on 6 subjects (20 yr) at 0700 h on days 1 and 2 after overnight fasts. On day 1, subjects also received either acetazolamide (250 mg, t.i.d) or placebo in randomized, double blind fashion. The results, as shown below, indicate that the small and rapid BW loss induced by acetazolamide reduces TBW and ECF. However, while BIA likely assessed accurately the reduction in ECF, it overestimated by 2x the possible change in TBW (assuming that 1 L of fluid = 1 kg BW). We conclude that BIA should not be used to assess acetazolamide-induced changes in TBW but may be useful assessing changes in ECF. The day 1 to day 2 changes (X ± SE; *P < 0.01 from placebo; #P < 0.01 from change in BW) were:Table: No Caption Available