Clinical application of new antihypertensive drugs
Within the past 2 years several new antihypertensive agents have been introduced for clinical use, and within the next 2 years it is anticipated that several more will be approved by the FDA. It is the purpose of this communication to describe some of these new agents and to indicate how they can be used to best advantage in the management of hypertension.
New sympathetic inhibiting agents
Propranolol (Inderal). The beta blocking agent propranolol which has been approved for managing angina pectoris, cardiac arrhythmias, pheochromocytoma, and idiopathic hypertrophic subaortic stenosis is being widely used for treating hypertension. Official FDA approval of propranolol for treatment of hypertension is expected momentarily.
It is an effective antihypertensive agent, especially when used in conjunction with an oral diuretic and hydralazine (Table). The mechanism of its antihypertensive action is not known, although numerous hypotheses have been advanced. It decreases cardiac output by blocking the beta receptors in the heart, but at the same time it increases peripheral resistance by blocking the beta receptors in the arterioles, stimulation of which causes vasodilation. It suppresses renin release by the kidney, but other beta blocking agents which do not suppress renin activity are equally effective as antihypertensive agents. Furthermore, propranolol does not suppress diuretic induced hyperreninemia, even though it produces an additional antihypertensive effect when added to a diuretic. Direct injection of propranolol into the cerebral ventricles of rabbits results in a prolonged depressor response, suggesting a central action.
Whatever its mechanism of action, and it may not. . .