Hemodynamic evaluation of hydralazine dosage in refractory heart failure

Hemodynamic responses to different doses of hydralazine were evaluated in 18 patients with severe refractory resistant heart failure. There were no significant overall hemodynamic effects after 50 mg hydralazine. After 75 mg, CI increased slightly (+0.36 l/min/m²), with a 19% decrease in SVR. After 100 mg, there were substantial increases in CI (+0.60 1/min/m²) and decreases in SVR (↓31 %) changes which were greater than those after 75 mg, but the decrease in MAP with 100 mg (-6.6 mm Hg) was of the same order as that after 75 mg (-5.0 mm Hg). LVFP and SWI improved significantly only with 100-mg doses. Seven patients in whom 100 mg hydralazine induced no hemodynamic effects all responded to single doses of 150 to 200 mg. The duration of action of hydralazine was longer (p < 0.001) in patients with a CCr < 35 ml/min (14.3 ± 1.4 hr) than in patients with adequate renal function (7.9 ± 0.5 hr). Thus, the dose and dosing interval of hydralazine needed to induce hemodynamic improvement in patients with severe heart failure are variable and require individualization.