Better renoprotective effect of angiotensin II antagonist compared to dihydropyridine calcium channel blocker in childhood

Background. The dihydropyridine calcium channel blocker amlodipine and the angiotensin II antagonist irbesartan effectively reduce blood pressure in hypertensive children. Methods. Eligible for the open-label, randomized study were nephropathic children between 6.0 and 18 years of age with plasma creatinine <177 mu mol/L, overt proteinuria, untreated arterial hypertension (systolic, 5 to 30 mm Hg; and diastolic, 1 to 15 mm Hg; >95th centile) and stable immunosuppressive treatment. The initial dose of amlodipine was 5 mg (body weight, 20 to 40 kg) and 10 mg (body weight, >40 kg), respectively, that of irbesartan, which was 75 mg (body weight, 20 to 40 kg) and 150 mg (body weight, >40 kg), respectively. The dosage was doubled if necessary. Results. A total of 26 children aged 6.1 to 17 years were allocated to receive either amlodipine (N = 13) or irbesartan (N = 13) for 16 weeks. Severe edema and headache occurred in two patients on amlodipine who withdrew from the study. No adverse experiences were noted in patients given irbesartan. Amlodipine [ by 12 (10 to 14)/7 (5 to 10) mm Hg; median and interquartile range, respectively] and irbesartan [by 13 (9 to 16)/9 (7 to 11) mm Hg, respectively] reduced blood pressure (P < 0.01) in a similar fashion. Heart rate, plasma sodium, and creatinine did not change. Irbesartan slightly increased plasma potassium [ by 0.1 (0.0 to 0.2) mmol/L; P < 0.05]. Plasma albumin and the urinary albumin/creatinine ratio were similar before and with amlodipine. On the contrary, irbesartan increased plasma albumin [by 4 (3 to 5) g/L; P < 0.03] and decreased the urinary albumin/creatinine ratio [by 242 (68 to 312) mg/mmol; P < 0.03]. Conclusion. The study demonstrates that in children the effect of angiotensin II antagonists on proteinuria is better than that of dihydropyridine calcium channel blockers.