Effects of Losartan and Enalapril on the Renal Function in Patients with Essential Hypertension

Objective To evaluate the effects of angiotensin Ⅱ receptor antagonist and angiotensin converting enzyme inhibitor on the renal function in patients of essential hypertension. Method A randomized, single-blind and parallel study was performed. After 1 week washout and 2 weeks placebo run-in period, 60 patients were randomly assigned to receive either 50 mg losartan ( n =30 ) or 5 mg enalapril ( n =30) once daily for 16 wks. If DBP ≥90 mmHg sustained after 4 wks treatment, the doses of both medications were doubled. At the end of run in period and 16 weeks after treatment, BP, HR, symptoms and signs were estimated; BP was measured by 24 h ambulatory blood pressure monitoring (ABPM). Before and after the treatment, the serum creatinine(Cr), blood urea nitrogen(BUN), endogenous creatinine clearance rate(Ccr), 24 h urine protein excretion [total urine protein(UTP), albumin(Alb)], urine α 1-microglobulin and β 2-microglobulin(α 1-MG and β 2-MG )excretion, urine sodium and potassium were measured. 20 healthy subjects were served as normal control group. Result ⑴ Losartan and enalapril significantly reduced the blood pressure of hypertensive patients after 16 weeks treatment. Blood pressure control in losartan group was similar to that in enalapril group. ⑵ Before treatment, Ccr was significantly lower in EH group than that in control group, UTP, Alb, urine α 1-MG and β 2-MG were significantly higher. ⑶ Both losartan and enalapril treatments decreased UTP and Alb, urine α 1-MG and β 2-MG after 16 weeks treatment. The changes were more significant in patients with disease duration10 years. ⑷ The prevalence of cough side effect in losartan group was significantly lower than that in enalapril group (6.7% vs 26.7%, P 0.01). Conclusion Losartan improve renal function effectively in patients with hypertension. The protective effects of losartan appears to be comparable to those of enalapril.