Cardiovascular and renal adjustments to a new hypotensive agent (Ciba-5968)

THE USE OF RADIOACTIVE MICROSPHERES TO COMPARE THE EFFECTS OF HYDRALAZINE, GUANETHIDINE AND SK&F 24260 ON THE REDISTRIBUTION OF CARDIAC OUTPUT IN ANAESTHETIZED RABBITS

“…The increase in cardiac output observed in rabbits using microspheres agrees with that in clinical studies by Wilkinson, Backman & Hecht (1952), Fries, Rose, Higgins, Finnerty, Kelley & Partenope (1953) and Stein & Hecht (1955). Similarly the large increases in renal and coronary flows agree with those found in man by Reubi (1950), Wilkinson et al (1952), Stein & Hecht (1955 and Crumpton, Rowe, Crosley, Maxwell & Huston (1953). Hydralazine is believed to lower blood pressure by dilatation of the pre-capillary resistance vessels (Ablad, 1963).…”

Hemodynamic Effects of 1-Hydrazinophthalazine in Patients With Arterial Hypertension 1

“…In spite of the increase in cardiac output, calculated left ventricular pressure work is not increased and the 02 consumption remains essentially the same. It seems clear that the vasodilatation produced by this drug is quite general since it is found in cerebral (15,16), hepatic (7,14), renal (11,17), and coronary vascular beds (18) as well as in the systemic and pulmonary vascular beds as a whole as shown in this study. However, the degree of vasodilatation is not the same in all areas (11,18).…”

“…It seems clear that the vasodilatation produced by this drug is quite general since it is found in cerebral (15,16), hepatic (7,14), renal (11,17), and coronary vascular beds (18) as well as in the systemic and pulmonary vascular beds as a whole as shown in this study. However, the degree of vasodilatation is not the same in all areas (11,18). Skin temperature was not found to increase generally by Wilkinson, Backman, and Hecht but did occur locally after direct intra-arterial administration (11).…”

“…A previous report of cardiac output after administration of Hydralazine was made by Wilkinson, Backman, and Hecht (11) The data from Group One suggest that the primary change after administration of Hydralazine to these patients with hypertension is a decrease in the vascular resistance both in the systemic cir-culation (-31 per cent) and in the lung (-28 per cent). Accompanying this decrease in vascular resistance there is a fall in systemic arterial pressure (-17 per cent) and a rise in cardiac output (+ 33 per cent).…”

Newer Drugs in the Treatment of Hypertension

“…The rise in renal blood flow is associated with increased cardiac output and tachycardia ;20 21 the latter effects can be presented by prior admifnistration of hexamethonium.2 Subsequent clinical investigations7' [23][24][25][26][27][28] have shown, with few exceptions, 29' 30 that hydralazine employed ( oncurrently with hexamethonium is more effective in the treatment of hypertension than either agent used alone. The present investigation was begun ill an effort to study the effects of combined hexamethonium-hydralazinie therapy in the longterm treatment of severe hypertension.…”