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Kidney Week

Abstract: PO0564

The Effect of Amiloride and Triamterene on Proteinuria in Patients with Proteinuric Kidney Diseases

Session Information

Category: CKD (Non-Dialysis)

  • 2102 CKD (Non-Dialysis): Clinical, Outcomes, and Trials

Authors

  • Alshehri, Mohammed, MedStar Georgetown University Hospital, Washington, District of Columbia, United States
  • Shen, Wen, MedStar Georgetown University Hospital, Washington, District of Columbia, United States
  • Desale, Sameer Y., Medstar Health Research Institute, Hyattsville, Maryland, United States
Background

Proteinuric kidney diseases are associated with a significant risk of developing end-stage renal disease. Treatment options after maximizing the renin-angiotensin-aldosterone system (RAAS) inhibition are limited. Amiloride, a diuretic inhibiting epithelial sodium channel (ENaC), has been reported to have antiproteinuric effects in animal studies independent of its action on ENaC. This study was designed to specifically examine the effect of Amiloride and triamterene in patients with significant proteinuria.

Methods

It is a cross-over pilot trial where each patient acted as his/her own control. Patients with proteinuria more than 1.0g/day, eGFR >30ml/min/1.73m2, and on the highest tolerable dose of angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) for at least 8 weeks were recruited. They received amiloride 5 mg twice daily or triamterene 50 mg twice daily for 8 weeks. All the patients then entered a washout phase for 4 weeks, followed by a crossover to the other trial drug for 8 weeks. Weight, blood pressure, metabolic panel, urine studies, and 24-hour urine protein excretion were frequently monitored. Patients with serum potassium >5.5 or an increase in serum Cr >30% one week after the treatment were withdrawn.

Results

A total of 12 patients were enrolled and completed the study. Amiloride reduced 24-hour urine protein by 25.4% (P=0.0435), UPCR by 31.6% (P=0.0104), UACR by 39.4% (P=0.0049). Triamterene reduced 24-hour urine protein by 33.7% (P=0.0153), UPCR by 29.4% (P=0.0130), UACR by 28.6% (P=0.0294). The effect on the 24-hour urine protein is not significantly different between the two drugs. The average change on the eGFR is -2 and -9 ml/min/1.73m2 in the amiloride and triamterene groups, respectively. Average systolic blood pressure reduction is 11 and 3 in amiloride and triamterene groups, respectively. The average change in the weight is -0.5 and -0.7 kg in amiloride and triamterene groups, respectively. Three patients exited the study due to hyperkalemia.

Conclusion

Both amiloride and triamterene showed the effect of proteinuria reduction regardless of the underlying pathology. This effect appears to be independent of the RAAS, given that patients were all on RAAS blockade. Large scale trials are needed to evaluate the antiproteinuric and renoprotection effects of ENaC inhibitors.