Hemodynamic effects of oxdralazine and hydralazine in hypertension.
Oxdralazine, a pyridazine shown to induce prolonged arteriolar dilation in animals, was given orally in doses of 15 to 30 mg to 7 subjects with hypertension. Arterial pressure fell in 2 hr (average mean of 16 mm Hg), peaking in 3 to 4 hr, and was sustained for more than 6 hr. Cardiac output and heart rate rose in 2 hr (2.1 l/min and 17 bpm) and were elevated at 6 hr (3.1 l/min and 22 bpm). Pulmonary arterial pressure and pulmonary arteriolar resistance did not change. In 6 subjects receiving oxdralazine with hydralazine 50 to 75 mg at 1-wk intervals, hydralazine induced earlier, less sustained decreases in arterial pressure and systemic vascular resistance and less of a rise in heart rate than oxdralazine alone. Circulating norepinephrine levels (radioenzymatic method) 3 hr after oxdralazine rose from a mean of 159 to 294 pg/ml, a greater (p less than 0.05) effect than after hydralazine. At the doses tested, oxdralazine is a potent systemic arteriolar dilator with longer-sustained action and more prominent reflex sympathetic stimulation than hydralazine.
D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D004983:Ethanolamines / Q000009:adverse effects / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D005542:Forearm / Q000098:blood supply; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D006830:Hydralazine / Q000009:adverse effects / Q000494:pharmacology* / Q000627:therapeutic use; D006973:Hypertension / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D011187:Posture; D011724:Pyridazines / Q000009:adverse effects / Q000494:pharmacology* / Q000627:therapeutic use; D013997:Time Factors; D014655:Vascular Resistance / Q000187:drug effects
D004983:Ethanolamines; D011724:Pyridazines; D006830:Hydralazine; C006198:oxdralazine; D009638:Norepinephrine