Dose Response and Safety of Telmisartan in Patients with Mild to Moderate Hypertension

This randomized, double-blind, double-dummy, placebo-controlled, parallel-group study evaluated the dose-response relationship of telmisartan in 207 patients with mild to moderate hypertension (diastolic blood pressure [DBP] 100 to 114 mmHg). After a 28-day placebo run-in period, patients were randomized to 28 days of once-daily, double-blind, double-dummy treatment with telmisartan 40, 80, or 120 mg; enalapril 20 mg; or placebo. Blood pressure (BP) was manually recorded for 12 hours after the first dose and after 24 hours at baseline (Day 0), Day 1, and Day 28 of double-blind treatment. Pharmacokinetic and pharmacodynamic parameters were assessed from telmisartan plasma concentrations. All doses of telmisartan and enalapril significantly reduced BP compared with placebo (p < or = 0.01). Mean +/- SE reductions in supine DBP after 28 days of treatment ranged between 7.9 +/- 1.3 mmHg and 9.8 +/- 1.3 mmHg in the telmisartan groups, 9.6 +/- 1.3 mmHg with enalapril, and 1.5 +/- 1.3 mmHg with placebo. Mean +/- SE reductions in supine systolic blood pressure (SBP) were between 10.0 +/- 2.2 mmHg and 15.5 +/- 2.2 mmHg with telmisartan versus 10.2 +/- 2.1 mmHg with enalapril; placebo increased supine SBP by 3.5 +/- 2.1 mmHg. The BP reductions after 4 weeks of treatment with telmisartan were no different from those achieved with enalapril. No significant linear trend in BP reduction was evident among telmisartan doses. Reductions in SBP and DBP were maintained over the 24-hour period at Day 28. Treatment did not affect supine heart rate. Trough/peak DBP ratios were > or = 85% for all telmisartan doses versus 65% for enalapril. High interpatient variability in telmisartan plasma concentrations was observed. For example, mean +/- SD values for Cmax were 159 +/- 104 ng/mL for telmisartan 40 mg, 693 +/- 606 ng/mL for telmisartan 80 mg, and 1635 +/- 1406 ng/mL for telmisartan 120 mg. Plasma concentration-effect analyses indicated that the antihypertensive effects of telmisartan 40, 80, and 120 mg are at the plateau region of the concentration-response curve. All active treatments were well tolerated, with tolerability profiles similar to placebo, and telmisartan did not produce any clinically relevant first-dose effects. These data confirm the antihypertensive efficacy and placebo-like tolerability of telmisartan.