Untoward effects of chronic dual renin-angiotensin system blockade: influence of previous chronic renal failure.

Dual blockade of the renin-angiotensin system (RAS) has increased antiproteinuric effects and so a higher incidence of secondary effects can be expected when this kind of treatment is administered. The aim of this study was to assess the safety of dual blockade of RAS. Seventy-five (54 men and 21 women) patients has been treated in our unit with dual RAS blockade due to proteinuria higher than 1 g/24 h. Mean age was 57.1 +/- 14.0 years. Fifty-three patients had chronic renal failure (CRF) at baseline. Analytical data of 6 months visit and last follow-up visit were recorded. A small reduction of systolic blood pressure and diastolic blood pressure was observed in both treatment groups throughout the study. Neither the CRF patients nor those with normal renal function showed any reduction in mean plasma haemoglobin levels, but differences between groups were significant at the second and third visits (anova). No change was detected in haematocrit. Mean K+ significantly increase at the second visit in the CRF group (from 4.80 +/- 0.64 to 5.23 +/- 0.81 mmol/l, p < 0.001, Student's t-test). There were no changes in normal kidney function group (4.58 +/- 0.37 vs. 4.63 +/- 0.44). At baseline plasmatic creatinine was higher in the CRF group (2.09 +/- 0.60 0.20 mg/dl vs. 0.99 +/- 0.20 mg/dl, p < 0.001, Student's t-test) and creatinine clearance was lower (48.6 +/- 20.7 ml/min vs. 107.0 +/- 0.30 ml/min, p < 0.001, Student's t-test). There was a small increase in creatinine along the follow-up when compared with the normal renal function group (p < 0.001, anova). Conversely, creatinine clearance remain unchanged in the normal renal function group, and there was a decrease in creatinine in CRF patients (p < 0.001). Dual RAS blockade seems to be safe in renal patients even when mild to moderate renal failure is present. Severe hyperkalaemia is uncommon. Small increments in plasmatic creatinine can be seen but they are hardly dangerous. Combined treatment does not significantly influence erythropoiesis.