Effects of felodipine versus nifedipine on exercise tolerance in stable angina pectoris

Current strategies for the prevention of angina in patients with stable coronary artery disease

PURPOSE OF REVIEW

Angina pectoris affects at least 6.6 million people in the US and approximately 400,000 new cases of stable angina occur each year. Angina may be one of the first signs of ischemic heart disease, although it is likely not causally related to the likelihood of plaque rupture leading to an acute coronary syndrome. Modalities for treatment of angina should be used maximally to improve quality of life and decrease cardiovascular morbidity and mortality. The current recommended pharmacologic and invasive approaches, as well as novel therapies, are reviewed.

RECENT FINDINGS

Antiischemic agents, including beta-blockers, nitrates and calcium channel blockers, remain the mainstay in the prevention of angina. Revascularization via percutaneous interventions or coronary bypass surgery are appropriate in specific cases or when medical treatment fails. Noninvasive treatment options for refractory angina, metabolic agents, and vasodilator therapies are adding to the armamentarium to prevent and treat angina.

SUMMARY

A multifaceted approach is optimal to address the prevention of angina. Once angina is recognized, there are many modalities that lessen the incidence of daily life-induced and exercise-induced angina and ischemia. Angina management is best addressed by pharmacologic and lifestyle interventions.

Felodipine and amlodipine in stable angina pectoris: results of a randomized double-blind crossover trial

A randomized, double-blind, crossover study tested the antiischemic and antianginal efficacy of felodipine, extended-release 5-10 mg, versus amlodipine, 5-10 mg once daily. Fifty-two patients with documented exercise-induced angina pectoris and myocardial ischemia during 24-h electrocardiographic monitoring were included in the study. Forty-seven patients completed the 8-week treatment period, whereas five patients withdrew from the study. The mean number of ischemic episodes/24 h was reduced from 19.9 at baseline to 2.3 during amlodipine and to 2.4 during felodipine; the total duration of ischemic episodes decreased from 69.8 min/24 h to 15.2 min and 15.5 min during amlodipine and felodipine, respectively (for both variables, p = 0.83 and p = 0.53 between treatments, and for both treatments, p < 0.001 compared with baseline). Eighteen (38%) patients receiving amlodipine and 19 (40%) patients receiving felodipine showed no ST-segment depression during treatment. Maximal ST-depression was reduced from an average of 2.1 mm to 1.1 and 1.2 mm on amlodipine and felodipine, respectively (p = 0.68 between treatments and p < 0.001 compared with baseline). Mean heart rate remained unchanged compared with baseline. Anginal attacks were reduced from 16.4/week at baseline to 4.7/week with amlodipine and to 4.3/week with felodipine (p = 0.26 between treatments, and p < 0.001 vs. baseline). Accordingly, nitrate consumption was reduced from 14.7 capsules per week to 4.0 and 3.8 with amlodipine and felodipine, respectively (p = 0.40 between treatments, and p < 0.001 compared with baseline). Adverse reactions were infrequent and distributed similarly between the two treatments. It is concluded that both drugs effectively reduced ischemic episodes and anginal attacks and were well tolerated in patients with stable angina pectoris. There was no evidence that the two regimens were different in their antiischemic and antianginal properties.

The efficacy of felodipine ER on regression of left ventricular hypertrophy in patients with primary hypertension

The aim of the study was to evaluate the efficacy over 1 year of of felodipine ER 5 and 10 mg once daily (od) in 12 Caucasian patients with left ventricular hypertrophy secondary to primary hypertension. After a placebo period of 20 days, a physical examination and an echocardiography were performed in each patient. All patients started treatment with felodipine ER 5 mg. In 3 of the 12 patients the dose was increased to 10 mg od to control blood pressure (BP). BP was recorded every 2 weeks during the first 3 months, and at monthly intervals from the 3rd to the 12th months. An echocardiogram was taken at the end of the 3rd, 6th, 9th and 12th months. At the end of the placebo period, the mean SBP/DBP (+/-SD) was 178 +/- 11/104 +/- 5 mmHg. Mean SBP and DBP decreased significantly (p < 0.001) during the first 2 months to 138 +/- 10/86 +/- 3 mmHg and remained at this level until the end of the study. Mean left ventricular mass index (LVMI) decreased from 170 +/- 33 g/m2 after the placebo period to 115 +/- 19 g/m2 after 1 year (p < 0.01). It is concluded that felodipine ER 5 and 10 mg od over 1 year statistically significantly reduced both BP and LVMI.

Vascular selective calcium entry blockers in the treatment of cardiovascular disorders: focus on felodipine

Calcium entry through L-type calcium channels is essential for contraction of both arterial smooth muscle and the myocardium, and is important in cardiac conduction. First-generation calcium entry blockers lack or have a modest degree of vascular selectivity and inhibit cardiac function at doses producing therapeutic arterial dilatation. Such agents may cause deterioration in patients with left ventricular dysfunction, and their combination with a beta-adrenergic blocker may adversely affect cardiac contractility and conduction. Development of newer agents has focused on obtaining a higher degree of vascular selectivity. Felodipine is a highly vascular selective calcium entry blocker, with a vascular selectivity ratio greater than 100, as shown experimentally. Isradipine and nicardipine are also vascularly selective calcium entry blockers. Hemodynamic studies in patients with hypertension, coronary artery disease, congestive heart failure, or in patients receiving beta-adrenergic blockade, show that felodipine can produce profound arteriolar dilatation without the negative effects of left ventricular systolic performance. Furthermore, felodipine alone or when added to a beta-adrenergic blocker does not interfere with cardiac conduction. The primary mechanism that accounts for the efficacy of dihydropyridine calcium entry blockers in hypertension and angina pectoris is arterial dilation, whereas nondihydropyridines may also derive part of their effect from inhibition of cardiac performance. As some of these patients, most commonly the elderly, have concomitant left ventricular dysfunction, it should be advantageous to avoid myocardial depression in the treatment of their primary disease. Preliminary studies in patients with heart failure indicate that felodipine and amlopidine may improve hemodynamics, reduce neurohormonal activation, and increase exercise tolerance, but final conclusions must await the randomized clinical trials now underway.