Abstract
The utility of nifedipine-GITS was evaluated in 185 patients with stable angina pectoris who were switched from immediate-release calcium antagonists to nifedipine-GITS. Efficacy and safety was based on the frequency of angina attacks, the frequency of sublingual nitroglycerin use, exercise capacity, and patient assessment of their quality of life and side effects to therapy. Overall, 165 (89%) of the 185 patients were successfully switched to nifedipine-GITS. The average frequency of anginal attacks, sublingual nitroglycerin use, and side effects were significantly less during nifedipine-GITS than during immediate-release calcium antagonist therapy. Exercise capacity was not significantly different during nifedipine-GITS therapy and immediate-release calcium antagonist therapy. The majority (87%) of patients reported either a stable or an improved quality of life following conversion to nifedipine-GITS. Of the 20 patients not successfully switched to nifedipine-GITS, 19 had an increased incidence of angina and one developed an intolerable side effect. The 19 patients with increased angina had received high doses of immediate-release calcium antagonists. Nifedipine-GITS may be safely and effectively substituted for immediate-release calcium antagonists in the majority of patients. Patients receiving high doses of immediate-release calcium antagonists may not be suitable candidates for conversion to nifedipine-GITS.