Vascular versus myocardial effects of calcium antagonists

Drugs
W C Little, C P Cheng

Abstract

As vascular smooth muscle tone and myocardial contractility both depend on calcium entry, the calcium antagonists are not only potent arterial vasodilators, but may also have important negative inotropic effects. For example, verapamil is nearly equipotent in reducing vascular smooth muscle tone and myocardial contraction in isolated tissue preparations. In contrast, felodipine has high vascular selectivity in such preparations, and drug concentrations required to depress myocardial contraction are more than 100 times greater than those required to relax vascular smooth muscle. In the isolated, isovolumetrically contracting canine left ventricle, clinically relevant concentrations of felodipine (14 nmol/L) produce coronary vasodilation and a mild positive inotropic response. Using left ventricular (LV) pressure-volume analysis, we evaluated a similar dose of felodipine (plasma drug concentration 16 nmol/L) in conscious dogs. Felodipine produced a 25mm Hg fall in arterial pressure and a 10% reduction in peripheral vascular resistance. There was no negative inotropic effect. Instead, myocardial contractile performance was slightly but significantly enhanced. These results were not altered by adrenergic blockade. Further studies i...Continue Reading

Citations

Nov 28, 2008·Rheumatology International·Sevdalina Nikolova Lambova, Ulf Müller-Ladner
Feb 13, 2001·The Journal of Clinical Investigation·R D CohnK P Campbell
Jul 3, 2007·Biological & Pharmaceutical Bulletin·Kwang-Seok OhByung Ho Lee
Aug 5, 2000·Clinics in Geriatric Medicine·D W Kitzman
Dec 26, 2016·Cellular and Molecular Life Sciences : CMLS·Serena StadlerGeorg Krupitza

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