Hemodynamic effects of nifedipine versus hydralazine in primary pulmonary hypertension.

The acute hemodynamic effects of both sublingual nifedipine (N) and intravenous hydralazine (Hy) were studied in 5 patients with primary pulmonary hypertension to ascertain whether the capacity for pulmonary vasodilatation was generalized or drug-specific, and to determine which of the 2 agents had preferential pulmonary vasodilatory effects. For the group as a whole, neither N nor Hy produced changes in heart rate, mean pulmonary capillary wedge or right atrial pressures. Both N and Hy reduced mean systemic arterial pressure (before N 90 +/- 8 mm Hg, after N 76 +/- 7 mm Hg, p less than 0.01; before Hy 92 +/- 11 mm Hg, after Hy 68 +/- 8 mm Hg, p less than 0.05), and decreased systemic vascular resistance (before N 1,558 +/- 645 dynes s cm-5, after N 1,192 +/- 430 dynes s cm-5, p less than 0.05; before Hy 1,700 +/- 415 dynes s cm-5, after Hy 957 +/- 285 dynes s cm-5, p less than 0.05). In addition, N administration resulted in an increased cardiac output (before N 4.5 +/- 2.0 liters/min, after N 4.8 +/- 2.0 liters/min, p less than 0.01); Hy administration was associated with a more varied effect on cardiac output (before Hy 4.0 +/- 1.0 liters/min, after Hy 5.3 +/- 1.8 liters/min, p less than 0.10, difference not significant [NS]).(ABSTRACT TRUNCATED AT 250 WORDS)