title: Effect of autonomic blockade on the hemodynamic responses of normal human subjects to acute intravenous milrinone.
abstract: We studied the hemodynamic effects of four doses of milrinone, administered by intravenous (i.v.) infusion alone and after autonomic blockade with prazosin, propranolol, atropine, and clonidine. Plasma concentrations of milrinone (50-600 ng/ml) were similar to those used for the treatment of cardiac failure and were unaltered by autonomic blockade. When given alone, milrinone induced dose-dependent increases in heart rate (maximum increase 21 +/- 4, SEM, beats/min) and cardiac output (CO) (maximum 44 +/- 9%) and reduced systemic vascular resistance (SVR) by a maximum of 32 +/- 5%. After autonomic blockade, milrinone caused a similar fall in SVR and a smaller but significant (7 +/- 2 beats/min) rise in heart rate, but no change in CO. The increase in CO produced in normal humans by acute i.v. infusions of milrinone depends on intact cardiovascular reflexes.
mesh_terms: D000328:Adult; D001340:Autonomic Nerve Block; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D020105:Milrinone; D011728:Pyridones / Q000097:blood / Q000494:pharmacology*
chemical_list: D011728:Pyridones; D020105:Milrinone