Renal and vascular protective effects of telmisartan in patients with essential hypertension

It is known that the angiotensin receptor blockers (ARBs) have organ protective effects in patients with heart failure or renal impairment. Several studies have revealed that the ARB telmisartan has an organ protective effect, but there have been few studies directly comparing the effects of telmisartan and calcium antagonists, since most clinical studies on telmisartan have been conducted in treated patients or patients on combination therapy. The present study was conducted to compare the renal and vascular protective effects of telmisartan monotherapy and calcium antagonist monotherapy in untreated hypertensive patients. Forty-three patients with untreated essential hypertension were randomized to receive amlodipine (n=22) or telmisartan (n=21), which were respectively administered at doses of 5 mg and 40 mg once daily in the morning for 24 weeks. The patients were examined before and after treatment to assess changes of renal function, flow-mediated dilation (a parameter of vascular endothelial function), and brachial-ankle pulse wave velocity (baPWV; a parameter of arteriosclerosis). Before treatment, there were no significant differences in these parameters between groups. The decreases of urinary albumin excretion and baPWV, and the increase of flow-mediated dilation were significantly greater in the telmisartan group than the amlodipine group, while the antihypertensive effects were not significantly different between the two groups. In conclusion, these results suggest that telmisartan is more effective at protecting renal function and vascular endothelial function, and at improving arteriosclerosis than the calcium channel blocker in patients with essential hypertension.