The angiotensin converting enzyme inhibitor perindopril and the diuretic indapamide have been shown to be effective antihypertensive agents in patients with chronic renal failure. A fixed low-dose combination of these two agents has been proposed in the treatment of hypertension. We evaluated this combination in 26 patients with mild to moderate essential hypertension and mild to severe chronic renal failure that did not require dialysis. This was a multicenter, open trial consisting of a 2-week single-blind placebo washout period followed by 12 weeks of active treatment. At week 0, the patients received 2 mg perindopril/0.625 mg indapamide once a day or every other day, with the possibility of dosage adjustment to perindopril 4 mg/indapamide 1.25 mg at week 2, week 4, or week 8. A pharmacokinetic analysis using a population pharmacokinetic approach was performed at week 8. Twenty-three patients completed the 12-week study, at which time 14 patients were receiving 2 mg perindopril/0.625 mg indapamide daily, three were receiving 2 mg perindopril/0.625 mg indapamide every other day, and six perindopril 4 mg/indapamide 1.25 mg. Blood pressure readings (supine) decreased from 170.4+/-19.2 / 101.5+/-6.7 mm Hg before active treatment to 146.5+/-19.7 / 86.5+/-10.6 mm Hg at the end of treatment (P < .0001). Pharmacokinetic analysis showed that for indapamide and perindoprilat (the active metabolite of perindopril) the area under the curve (AUC24) increased with the severity of renal failure. No interaction was noted between the two drugs. Mean serum creatinine and sodium and serum potassium levels remained stable during the study. Impairment of renal function occurred in one patient and was considered unrelated to treatment. We conclude that a fixed low-dose perindopril-indapamide combination as first-line treatment has a good safety/efficacy ratio in hypertensive patients with chronic renal failure.