Protecting the vasculature: an eye toward the future. Although calcium antagonists were originally developed for use in the management of patients with angina pectoris, they are now used in the management of other cardiovascular disorders, including hypertension. More recently, the calcium antagonists have been under investigation for their potential protective role in atherosclerosis. Coupled with these new possibilities for therapeutic use are the development of new, long-acting, tissue-specific calcium antagonists. Amlodipine belongs to this group, and although it is a dihydropyridine-based calcium antagonist, its pharmacologic profile differs from that of other dihydropyridine-based calcium antagonists. Differences include: different pH optimum for receptor binding, different rates of association and dissociation, and differences in allosteric interaction with the diltiazem and verapamil binding sites. Amlodipine, when given orally to rabbits receiving a high-cholesterol diet, reduces atheroma formation. Evidence of its ability to protect the vasculature is provided by its ability to significantly increase (p less than 0.001) survival in stroke-prone hypertensive rats. 