title: Hemodynamic effects of a new inotropic agent, piroximone (MDL 19205), in patients with chronic heart failure.
abstract: The hemodynamic and neurohumoral effects of cummulative intravenous doses of piroximone (MDL 19205), a noncatecholamine, nonglycoside, imidazole derivative with positive inotropic and vasodilating properties, were studied in eight patients with severe congestive heart failure. A dose of 1.25 mg/kg in seven patients and 1.75 mg/kg in one patient increased cardiac index by 75% from 1.96 to 3.41 liters/min per m2 and decreased systemic vascular resistance (-41%), right atrial (-66%) and pulmonary wedge pressure (-35%) (all p less than 0.005). Mean arterial pressure was slightly reduced from 78 to 71 mm Hg (p less than 0.05) and forearm blood flow increased by 42%. Plasma norepinephrine decreased from 830 to 542 pg/ml (p less than 0.05) and plasma renin activity tended to increase. In four patients, dobutamine (15 micrograms/kg per min) produced a comparable increase in cardiac index (+100%), but less decrease in pulmonary wedge pressure (-21 versus -41%, p less than 0.05 versus piroximone) and, unlike piroximone, significantly increased heart rate (+22%, p less than 0.05 versus piroximone) and heart rate-blood pressure product (+30%, p less than 0.01 versus piroximone). In four other patients, a single intravenous dose of piroximone (1 mg/kg) resulted in a 35% increase in the first derivative of left ventricular pressure (dP/dt) from 796 to 1,068 mm Hg/s (p less than 0.01). Thus, piroximone is a potent inotropic agent with an acute hemodynamic profile that may be more favorable than that of dobutamine. Because the drug is orally absorbed, clinical trials of chronic efficacy are indicated.
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D004280:Dobutamine / Q000097:blood / Q000494:pharmacology / Q000627:therapeutic use; D006333:Heart Failure / Q000188:drug therapy* / Q000503:physiopathology; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007093:Imidazoles / Q000097:blood / Q000494:pharmacology / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000187:drug effects; D011651:Pulmonary Artery / Q000503:physiopathology; D011669:Pulmonary Wedge Pressure / Q000187:drug effects; D013268:Stimulation, Chemical; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D007093:Imidazoles; C039686:piroximone; D004280:Dobutamine