Nitrendipine solution 5 mg.ml-1 in the dose of 5 mg was given orally to 20 patients with chronic renal failure and elevated diastolic blood pressure (> or = 110 mmHg), of whom 10 were on maintenance haemodialysis (endogenous creatinine clearance < 5 ml.min-1) and 10 were at the predialysis stage (endogenous creatinine clearance 5-20 ml.min-1). The aim of the study was to investigate the influence of kidney function and/or dialysis treatment on the pharmacokinetic and pharmacodynamic profile of a solution of nitrendipine and to assess its antihypertensive efficacy. After 10 min there was a significant reduction in blood pressure from 188/113 to 173/100 (patients not dependent on dialysis) and from 197/112 to 161/94 mmHg (patients dependent on dialysis). The maximum fall in blood pressure (approximately 30%) was attained after 90 min in the dialysis patients and after 120 min in the non-dialysis group. Blood pressure increased again about 3 h after the administration of nitrendipine but it was still below baseline after 12 h. The terminal elimination half-life (4.1 h in the dialysis patients and 3.6 h in non-dialysis patients) was similar to that observed in patients with normal renal function. The pharmacokinetics of nitrendipine did not differ between the dialysis and non-dialysis groups. There was a correlation between plasma concentration and the blood pressure reduction. The maximum plasma concentration of nitrendipine was reached after 0.5 h (median) and did not differ between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)