Increasing use of longer-acting dihydropyridines

Introduction and growth of new prescriptions of differing formulations of nifedipine and of amlodipine since 1986. Nifedipine was only available in the United States as a short-acting formulation in the late 1980s. The slow-release GITS (gastrointestinal therapeutic system) formulation of nifedipine was not introduced until 1989, and its usage did not increase appreciably until 1991-1992; the usage of amlodipine began to increase in 1993.