Further Observations on the Effects of Autonomic Blocking Agents in Patients with Hypertension

Moderate reduction in blood pressure by intravenous hexamethonium or pentamethonium was accompanied by a decrease in stroke volume, cardiac output, and left ventricular work, and no change or an increase in peripheral resistance. Renal blood flow, filtration rate, and potassium clearance fell promptly, but returned to the original levels within one to two hours despite continued reduction in blood pressure. Sodium clearance and urine flow were reduced to a greater extent and returned more slowly. Oral hexamethonium produced some reduction in renal blood flow, and improvement in the ballistocardiogram. Oral hydrazinophthalazine diminished the effect of hexamethonium on renal blood flow.