[Effect of furosemide on water and sodium excretion in apparently normal infants]

Nine infants without evidence of nephropathy were studied. After a control period, furosemide, 1.0 mg/kg. of body weight, was administered intravenously and urine was collected. In all patients, urinary volume increased from a mean of 0.15 ml/min. during the control period, to 0.69 ml/min. after furosemide and urinary sodium excretion rose from 1.77 micro Eq/min. in the first period, to 50.13 micro Eq/min. in the second. There was no significant change in urinary osmolarity and in serum electrolytes. Three hours after furosemide, all children showed dehydration from light to moderate and saline infusion was necessary. No correlation was found between age and weight of the infants with the response to furosemide. Because this diuretic has an energetic action in infants as in children and adults, it must be used carefully and it is proposed that the initial dose of furosemide in infants be 0.5 mg/kg.