Changes in Plasma Volume and Extracellular Fluid Volume after Addition of Hydralazine to Propranolol Treatment in Patients with Hypertension

Abstract

In 16 patients with hypertension, BP [blood pressure] could not be controlled satisfactorily by treatment with propranolol alone (mean dosage 325 mg/day). Plasma volume (PV) (T-1824) and extracellular fluid volume (ECV) (82Br-distribution space) were determined in these patients before and after the addition of hydralazine for 3 mo. (mean dosage 135 mg/day). After the addition of hydralazine, PV and ECV increased significantly, by 9 and 3%, respectively. Systolic and diastolic BP decreased, by 15 and 13%. The mechanisms inducing fluid retention during treatment with hydralazine and the clinical significance of the problem are discussed. The addition of a diuretic to propranolol-hydralazine treatment is often well indicated.