title: Age-dependent cardiovascular effects of verapamil in newborn swine.
abstract: Since there are limited studies concerning the hemodynamic effects of verapamil in pediatric patients, cardiovascular effects of clinical doses (100 or 300 micrograms/kg) of verapamil, given as a 2-min intravenous infusion, were examined in sodium pentobarbital anesthetized swine, aged 1 day (n = 15) and 2 wk (n = 18). Aortic and left ventricular pressures, index of left ventricular contractility, heart rate, and phasic superior mesenteric, renal, and femoral arterial flows were recorded; mean aortic pressure and vascular resistances were calculated. Maximum changes in cardiovascular function (mean % delta +/- SEM) occurred at the end of the infusion. Mean aortic pressure and index of left ventricular contractility decreased in all animals; responses were larger in magnitude with the higher dose. By 30 min after infusion of 300 micrograms/kg verapamil had ended, mean aortic pressure in both 1 day and 2 wk olds and index of left ventricular contractility and femoral flow in 1 day olds were still decreased. During infusion of verapamil, heart rate decreased (-11.6 +/- 2.9) to the high dose in 1 day olds but increased (+6.4 +/- 2.7) to 100 and 300 micrograms/kg verapamil in 2 wk olds. After infusion of 300 micrograms/kg verapamil ended, heart rate decreased and reached the nadir (-10.0 +/- 2.9) by 10 min in 2 wk olds. Decreases in renal resistance (-7.6 +/- 1.7) were not dose dependent while superior mesenteric resistance decreased (-12.9 +/- 2.7) only to low dose verapamil in 2 wk olds. In 1 day olds decreases in renal and superior mesenteric resistance were not sustained throughout the infusion.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000375:Aging; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001794:Blood Pressure / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D009200:Myocardial Contraction / Q000187:drug effects; D012039:Regional Blood Flow / Q000187:drug effects; D013552:Swine; D014655:Vascular Resistance / Q000187:drug effects; D014700:Verapamil / Q000494:pharmacology*
chemical_list: D014700:Verapamil