A randomized trial comparing losartan with amlodipine as initial therapy for hypertension in the early post-transplant period

BACKGROUND: Blockade of the renin-angiotensin-aldosterone system in the early post-transplant period remains controversial. Angiotensin II-receptor blockers (ARB) have many benefits to the patient with chronic kidney disease and these benefits may also apply to the renal transplant recipient (RTR). Additionally, there are theoretical benefits of ARB use in RTR. This study was designed to investigate the safety of early ARB use after renal transplantation. METHODS: RTR with serum creatinine levels <3.0 mg/dl were randomized to receive either ARB (n = 29) or calcium-channel blocker (CCB; n = 27) as initial therapy for post-transplant hypertension. Differences in potassium, creatinine and haemoglobin concentrations were compared at baseline, 3, 6 and 12 months after transplantation. RESULTS: Withdrawal from the assigned treatment was high: 12 in the ARB group (due to hyperkalaemia in six) and 17 in the CCB group (due to intractable oedema in seven and post-transplant erythrocytosis requiring an angiotensin-converting enzyme inhibitor in seven). There were no differences in blood pressure, haemoglobin or creatinine concentration at any time-points. Mean potassium concentrations were only slightly higher in the ARB vs CCB group (range: 4.2-4.3 vs 3.7-3.8 mEq/l, respectively, but clinically significant) and the number of patients with potassium values >6.0 mEq/l was higher in ARB (n = 7) vs CCB (n = 1). CONCLUSIONS: These data suggest that hyperkalaemia is the major complication that occurs with the use of ARB in the immediate post-transplant period. ARB use does not affect renal function or complicate the post-transplant management of RTR. Other than reducing the incidence of post-transplant erythrocytosis, ARB use does not cause an excess incidence of anaemia. Strategies to reduce the risk of hyperkalaemia may allow increased use of ARB immediately after kidney transplantation.