The Association of Long Term Furosemide Therapy with Calciuria and Nephrolithiasis 343

Abstract

Background: Furosemide has been found to induce significant calciuria and also nephrocalcinosis and nephrolithiasis in neonates. Objectives: We designed a prospective study to test the hypothesis that long term furosemide therapy in a group of children with heart disease who were taking this drug as a part of their treatment may induce significant calciuria, nephrocalcinosis and/or nephrolithiasis (furosemide group). We compared them with a group of healthy children who did not receive furosemide(control group). Methods: We measured serum calcium, urea and creatinine, urine pH, urine calcium and creatinine ratio. We did renal ultrasonographic examinations for every child who was found to have significant calciuria (Ca/Cr. Ratio >0.25). Results: The furosemide group consisted of twenty patients taking furosemide for periods ranging between two weeks to five years, and no history of renal disease. Their ages were between 16 months and 13 years, sex distribution was 9 males and 11 females. The control group (12 children) were selected from the out patient clinic (of comparable age and sex distributions). They came to the clinic for minor illnesses with no history of renal diseases or diuretic therapy. No difference in serum calcium or urine pH levels were detected between the furosemide and control groups. In the furosemide group, sixteen were found to have significant calciuria, fourteen of them were examined by renal ultrasonography. Eight of them were found to have nephrolithiasis. No one in the control group was found to have significant calciuria. Conclusion: In children with heart disease the use of furosemide as a chronic diuretic therapy leads to significant calciuria and more than half of them may have nephrolithiasis. Further studies are needed to define these risks with furosemide therapy and perhaps find alternative methods of treatment that are less dangerous to the renal system.