Direct comparison of the effects of valsartan and amlodipine on renal hemodynamics in human essential hypertension.
BACKGROUND
To elucidate the renoprotective mechanism of AT(1)-receptor blockers, we compared the effects of the AT(1)-receptor blocker valsartan with those of the calcium channel blocker amlodipine on renal hemodynamics and microcirculation.


METHODS
A total of 58 patients (50.2 +/- 9.0 years) with mild to moderate essential hypertension were included in a randomized, double-blind study to receive either valsartan (80 to 160 mg) or amlodipine (5 to 10 mg). Renal plasma flow (RPF) and glomerular filtration rate (GFR) were measured before and after 8 weeks of treatment. Glomerular hydrostatic pressure (P(Glo)) and resistances of the afferent (R(A)) and efferent (R(E)) arterioles were calculated according to the Gomez formulas.


RESULTS
Blood pressure control was similar in both groups. RPF did not change with either treatment. In contrast, GFR increased with amlodipine (+8 +/- 14 mL/min; P <.01) but was preserved with valsartan. Amlodipine caused a more marked increase in the R(E)/R(A) ratio than valsartan (+0.26 +/- 0.26 v +0.13 +/- 0.24, P <.05), which was paralleled by an increase in P(Glo) in patients treated with amlodipine (+1.9 +/- 4.3 mm Hg; P <.05) but not in those treated with valsartan.


CONCLUSIONS
At similar blood pressure control, valsartan maintained GFR and P(Glo), whereas amlodipine led to glomerular hyperfiltration and an increase in P(Glo). The results might explain the favorable renal outcome with AT(1)-receptor blocker therapy.
Delles
Christian
C
Department of Medicine IV/4, University of Erlangen-Nürnberg, Nuremberg, Germany.
Klingbeil
Arnfried U
AU
Schneider
Markus P
MP
Handrock
Renate
R
Weidinger
Gottfried
G
Schmieder
Roland E
RE
D017311:Amlodipine / Q000494:pharmacology* / Q000627:therapeutic use; D000959:Antihypertensive Agents / Q000494:pharmacology* / Q000627:therapeutic use; D004311:Double-Blind Method; D005919:Glomerular Filtration Rate / Q000187:drug effects*; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D008833:Microcirculation / Q000187:drug effects; D008875:Middle Aged; D012079:Renal Circulation / Q000187:drug effects*; D013777:Tetrazoles / Q000494:pharmacology* / Q000627:therapeutic use; D014633:Valine / Q000031:analogs & derivatives / Q000494:pharmacology* / Q000627:therapeutic use; D000068756:Valsartan
D000959:Antihypertensive Agents; D013777:Tetrazoles; D017311:Amlodipine; D000068756:Valsartan; D014633:Valine