Comparison of venodilatory effect of nicardipine, diltiazem, and verapamil in human subjects.
OBJECTIVE
Venodilatory effects of calcium antagonists have not been fully investigated, especially in human subjects. The present study was undertaken to compare the direct venodilatory effects of nicardipine, diltiazem and verapamil using the dorsal hand-vein technique.


METHODS
In eight healthy male subjects, increasing doses (0.001, 0.01, 0.1, 1 and 10 microg x min(-1)) of these drugs and saline alone were infused, on four separate occasions, into the dorsal hand vein preconstricted with noradrenaline, and its diameter was measured by a linear-variable differential transformer.


CONCLUSIONS
Diltiazem caused significant venodilation at a dose of 0.01 microg x min(-1) or more, while verapamil and nicardipine only caused this effect at 1 microg x min(-1) or more. The potency of the effect was diltiazem > verapamil > nicardipine. The venodilation at a dose of 1 microg x min(-1) was 41.7%, 16.2% and 8.5%, respectively, for each drug. These findings indicate that the venodilatory effect of diltiazem is larger than that of verapamil and nicardipine in human subjects.
Harada
K
K
Department of Clinical Pharmacology, Jichi Medical School, Tochigi, Japan.
Ohmori
M
M
Sugimoto
K
K
Fujimura
A
A
D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004110:Diltiazem / Q000494:pharmacology*; D006225:Hand / Q000098:blood supply; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D009529:Nicardipine / Q000494:pharmacology*; D014665:Vasodilator Agents / Q000494:pharmacology*; D014680:Veins / Q000187:drug effects* / Q000502:physiology; D014700:Verapamil / Q000494:pharmacology*
D002121:Calcium Channel Blockers; D014665:Vasodilator Agents; D014700:Verapamil; D009529:Nicardipine; D004110:Diltiazem