Limitation on the use of amiloride in early renal failure.
The effect of a single oral dose of 10 mg amiloride was studied on urinary excretion of Na+, K+, Ca++ and Mg++ in healthy subjects and in patients with varying degrees of renal impairment. Amiloride produced a moderate diuresis and sodium excretion, and a slight calciuresis. Urinary excretion of potassium was significantly reduced as compared to the controls. Despite its diuretic and natriuretic effects, amiloride did not change the excretion of Mg++ as compared to the pretreatment period. When the creatinine clearance was below 50 ml/min, the net excretion of Na+ and Ca++ was drastically reduced. However, K+ retention and neutrality of Mg++ excretion were maintained down to end-stage renal disease. In the healthy volunteers the mean elimination half-life of amiloride was 20 h, and it rose to about 100 h in end-stage renal disease. This was because about 3/4 of native amiloride was eliminated through the kidney. Nonrenal elimination of amiloride was calculated to amount to only 1/4 of the total elimination. Therefore, the anticaliuretic amiloride is a valuable comedication in subjects with normal kidney function to prevent K+ and Mg++ loss. However, its use is hazardous if plasma creatinine is raised.
D000328:Adult; D000368:Aged; D000584:Amiloride / Q000009:adverse effects* / Q000378:metabolism / Q000627:therapeutic use; D002118:Calcium / Q000652:urine; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000188:drug therapy* / Q000652:urine; D007700:Kinetics; D008274:Magnesium / Q000652:urine; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000652:urine; D011719:Pyrazines / Q000009:adverse effects*; D012964:Sodium / Q000652:urine; D013050:Spectrometry, Fluorescence; D013997:Time Factors
D011719:Pyrazines; D000584:Amiloride; D012964:Sodium; D008274:Magnesium; D011188:Potassium; D002118:Calcium