Influence of digoxin and diuretic therapy on sweat fluid composition.

The effect of digitalis and diuretic therapy on sweat fluid composition was investigated. Patients treated for congestive heart failure with a combination of digoxin and diuretics demonstrated a higher concentration of sodium and chloride in their sweat fluid when compared to age-matched controls. The administration of diuretics alone did not affect sweat fluid composition. The digoxin-induced increase in sodium concentration was significantly higher than that observed for chloride. These data suggest that digoxin markedly inhibits sodium reabsorption along the sweat gland tubule, whereas chloride transport is affected to a lesser degree. A significant correlation between sweat fluid sodium and serum digoxin concentrations was observed. We conclude that the increased digoxin-induced sweat sodium and chloride losses may affect sodium homeostasis in patients with congestive heart failure.