The Journal of laboratory and clinical medicine
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Furosemide stimulates urinary acidification in normal humans probably by increasing distal Na delivery and transport, thus creating a favorable electric gradient for H+ and K secretion. Therefore, furosemide should stimulate urinary acidification in patients with distal renal tubular acidosis, provided the distal nephron is capable of transporting Na and the H+ pumps can respond to the favorable electric gradient. We examined the effect of short-term furosemide administration on urinary acidification in five normal participants and 12 patients with normokalemic, hypokalemic, or hyperkalemic distal renal tubular acidosis. ⋯ The patients with voltage-dependent defect did not lower urine pH or increase net acid and K excretion. Our data demonstrate that administration of furosemide enhances urinary acidification in certain patients with distal renal tubular acidosis. We suggest that furosemide administration may be useful in the characterization of the mechanism responsible for distal renal tubular acidosis and in the treatment of distal renal tubular acidosis in selected patients.