Amlodipine, a dihydropyridine calcium antagonist, was administered at 2.5-5.0 mg/day for 8 weeks to 35 hypertensive patients with renal dysfunction, and its efficacy and safety were evaluated. The target reduction in blood pressure was achieved in 28 of the 35 patients (80%), while blood pressure was decreased in 4 patients (11.4%) and unchanged in 3 patients (8.6%). A side effect of mild headache was reported by one patient (2.9%). In addition, abnormal changes in laboratory values were observed in five patients, but all of the changes were mild. Blood urea nitrogen and serum creatinine levels both increased in two of these five patients, and serum creatinine levels increased in another two patients. Serum amlodipine concentration was 4.86 +/- 2.57 ng/ml (n = 8) and 3.01 +/- 1.02 ng/ml (n = 8) in patients receiving a daily dose of 2.5 mg for 2-5 weeks and 8-10 weeks, respectively. Serum concentration in patients receiving 5 mg from Weeks 2-6 was 9.72 +/- 6.89 ng/ml (n = 6) after 7-9 weeks, suggesting no tendency for the accumulation of this drug. The drug was rated as of clinical benefit in 27 of the 35 patients (77.1%), and as slightly beneficial in another 5 patients (14.3%). Thus, amlodipine significantly decreased the blood pressure while causing little or no aggravation of renal dysfunction in hypertensive patients with renal impairment.
