Evaluation of the safety and efficacy of telmisartan and enalapril, with the potential addition of frusemide, in moderate-renal failure patients with mild-to-moderate hypertension

The effect on renal function and efficacy of the angiotensin II AT 1 -receptor blocker (ARB), telmisartan, were compared with those of the angiotensin-converting enzyme inhibitor, enalapril, for the treatment of mild-to-moderate hypertension (diastolic blood pressure [DBP] 95—114 mmHg) in the presence of moderate renal failure (creatinine clearance [Ccr] 30—80 ml/minute). The study was multicentre, double-blind, double-dummy and active-controlled in design, with patients randomised in a 2:1 ratio to receive telmisartan or enalapril. After a two-week placebo run-in period, the 71 eligible patients received either telmisartan, 40 mg, or enalapril, 10 mg, once-daily for four weeks. Thereafter, doses were titrated to telmisartan 80 mg or enalapril 20 mg once-daily if supine trough DBP was still ≥90 mmHg. After a further four weeks, dose titration was again performed, as required, to telmisartan, 80 mg, or enalapril, 20 mg, or frusemide was given in addition if the double dose was already being administered. Mean Ccr decreases of 4.6% for telmisartan and 2.8% for enalapril were not clinically significant. Adverse events occurred in 12 (26.7%) telmisartan-treated patients and in 12 (46.2%) patients receiving enalapril. The mean reduction in supine trough DBP from baseline to the last available value was 12.5 mmHg for telmisartan, compared with 11.9 mmHg for enalapril. A full (reduction of ≥10 mmHg) or partial (reduction of 7—9 mmHg) response occurred in 78% of telmisartan patients and 65% of enalapril patients. In the enalapril group, 43% of patients required frusemide, compared with 29% of those in the telmisartan group. In conclusion, telmisartan lacks detrimental effect on renal function, is effective in the treatment of mild-to-moderate hypertension in patients with moderate renal failure, and is comparable to enalapril.