A double-blind evaluation of amlodipine in patients with chronic, stable angina: sustained efficacy and lack of "withdrawal phenomenon" upon abrupt discontinuation.

To date, the clinical utility of first-generation, shortacting calcium antagonists has not been optimal due to their multiple dosing requirements. This has led to poor compliance in some patients. In this study, the safety and efficacy of a new generation dihydropyridine calcium antagonist, amlodipine (5-10 mg once daily) were evaluated in patients with chronic, stable angina pectoris. Amlodipine monotherapy was given to 226 patients over an 8-week, single-blind period, and the responders (> or = 7% improvement in exercise time) then underwent a randomized, placebo-controlled, double-blind withdrawal phase, lasting for a further 4 weeks. Amlodipine was shown to be both effective and well-tolerated in patients with chronic, stable angina pectoris. There was no evidence for the development of tolerance to amlodipine over a total of 3 months and there did not appear to be any significant problems (of the type noted with abrupt beta-blocker cessation) associated with its withdrawal.