Calcium antagonists for initial therapy of hypertension

A new class of antihypertensive agents has emerged for clinical consideration in the initial treatment of hypertension. These calcium antagonists are rapidly absorbed and reduce arterial pressure very promptly by antagonizing the pathophysiologic hallmark of the disease: an increased vascular resistance. Moreover, in reducing arterial pressure by means of arteriolar dilation, these agents do so without expanding intravascular volume and without inordinately stimulating the heart through reflex mechanisms. Vascular resistance is reduced in each of the major target organs of the disease: the heart, brain, and kidney. Reduction of coronary vascular resistance should be of particular value in patients with increased myocardial oxygen demands (e.g., with coronary arterial disease or with ventricular hypertrophy). Reduction of renal vascular resistance should be especially valuable for patients with renal functional impairment as a result of hypertensive vascular disease or with associated renal parenchymal diseases. In this respect, these agents reduce renal vascular resistance while maintaining glomerular filtration rate and reducing renal filtration fraction; these changes should reduce glomerular hyperfiltration and may inhibit promotion of glomerulosclerosis. Diltiazem may be of particular value because it may produce these effects while increasing renal blood flow. Clearly these agents reverse cerebral constriction and might be expected to improve blood flow to the brain; however, further study is anticipated and necessary.