New calcium antagonists: relevance of vasoselectivity. The calcium antagonists are a heterogeneous class of drugs used to treat a number of cardiovascular disorders. A new generation of calcium antagonists under development have a higher degree of selectivity for vascular smooth muscle and coronary vasculature compared with verapamil, nifedipine, and diltiazem. The clinical relevance of vasoselectivity and its impact on drug selection are discussed. The newer calcium antagonists are important alternatives to older agents and may be associated with improved tolerance and a reduced incidence of adverse effects. Their place in therapy has yet to be defined by comparative studies of efficacy and safety. 