The effect of furosemide on sodium and potassium concentrations in guinea-pig perilymph.

To observe the effects of furosemide on electrolyte concentrations in inner-ear fluids, experiments were performed on 286 normal guinea-pigs. Intravenous injection of furosemide (15 mg/kg) induced increases of Na concentration in scala tympani perilymph, scala vestibuli perilymph, and cerebrospinal fluid (CSF). K concentrations in both perilymphs and CSF were also increased by furosemide. The increased Na concentrations are thought to be due to the dehydration of body fluids induced by the diuretic action of furosemide. The increase of K concentrations in perilymphs could be attributable to either a characteristic action of furosemide on the electrolyte transport in the inner ear or a secondary change caused by a rise of K concentration in the endolymph.