Irbesartan effects on renal function in patients with renal impairment and hypertension: a drug-withdrawal study

The blood-pressure lowering activity, tolerability, and safety of irbesartan was evaluated in 52 hypertensive patients with chronic renal insufficiency. After a 3-week placebo period, once-daily irbesartan was administered for 12 weeks at a daily dose of 150 mg titrated to 300 mg. A second, non-angiotensin-converting enzyme inhibitor, antihypertensive drug was added after 8 weeks as needed. Twenty-four-hour creatinine clearance was determined and renal clearance studies of inulin and para-aminohippurate were done in a subset of 11 patients. Trough sitting blood pressures were reduced at the end of the first week in all groups. At weeks 4, 8, and 12 the reductions in systolic blood pressure/diastolic blood pressure averaged -11.9/-8.7, -10.8/-9.4, and -14.7/-12.1 mm Hg in patients with mild renal insufficiency and -7.7/-6.3, -13.1/-11.8, and -14.1/-10.6 mm Hg in patients with moderate-to-severe renal insufficiency. Creatinine clearance, glomerular filtration rate, and effective renal plasma flow were stable. Irbesartan was withdrawn in only five patients because of adverse clinical or laboratory experience. Hyperkalemia (>6 mEq/l) requiring discontinuation of irbesartan occurred in only one patient. Once-daily irbesartan given as monotherapy at dose of 150-300 mg or in combination with other antihypertensive drugs is effective in reducing blood pressure in hypertensive patients with chronic renal disease. Irbesartan regimens are well tolerated in all groups. In addition, the blood pressure-lowering effect of irbesartan is accompanied by a significant reduction in proteinuria in patients with chronic renal insufficiency.