OACE INHIBITION DOES NOT INTERFERE WITH ACUTE EXTRARENAL OR RENAL POTASSIUM DISPOSAL IN CHRONIC-RENAL-FAILURE

The influence of angiotensin converting enzyme (ACE) inhibition on acu te extrarenal and renal potassium elimination in stable chronic renal failure has been examined in 10 male patients median age 44 y; mean CL (CR) 42 ml . min(-1.) 1.73 m(-2). In a double blind, placebo-controlle d cross-over study, K+ 0.3 or 0.4 mmol . kg(-1) body weight was infuse d IV on two occasions while the patients also received an infusion eit her of placebo or 0.5 mg of the ACE inhibitor perindoprilat in random order. Plasma K+ levels and urinary K+ excretion were measured at regu lar intervals. During the study patients adhered to an isocaloric diet providing a standardised daily intake of potassium and sodium (50 mmo l K+ and 30 mmol Na+). The median rise in plasma K+ was not significan tly different after placebo (Delta K 0.66 mmol . 1(-1)) compared with to the infusion of perindoprilat (Delta K 0.66 mmol . 1(-1)). The medi an baseline urinary Iii excretion rate was 6.5 mmol . 3 h(-1) before t he placebo infusion and 5.9 mmol . 3 h(-1) before infusion of perindop rilat. During the potassium load, the urinary excretion rate rose to 1 6.1 mmol . 3 h(-1) (after placebo) and 15.1 mmol . 3 h(-1) after perin doprilat in the first 3 h, and it returned almost to the baseline valu e within the next 3 h (5.6 mmol . 3 h(-1) after placebo and 5.7 mmol . 3 h(-1) after perindoprilat); the differences were not statistically significant. With perindoprilat a decrease in mean arterial blood pres sure and ACE activity. an increase in renin plasma activity and a decr ease in aldosterone concentrations were observed compared to the place bo infusion. There was no significant differences plasma in adrenaline or insulin levels after either infusion. Thus, ACE inhibition did not interfere either with the extrarenal or the renal disposal of an acut e potassium load in patients with chronic renal failure.