Selection of optimal drug therapy for the patient with angina pectoris

Management of Coronary Heart Disease: Stable Angina, Acute Coronary Syndrome, Myocardial Infarction

Stable angina should first be treated medically, particularly with aspirin and beta-blockers. Diagnostic stress tests are used in patients who have intermediate probability of CHD to further assess the likelihood of disease,with catheterization reserved for patients who have symptoms despite optimal medical therapy or are at risk for multivessel CHD. The work-up for low-risk unstable angina can involve medical management followed by stress testing. Moderate-to-high risk unstable angina and NSTEMI should be treated with an integrated approach, using medical therapy, cardiac catheterization, and revascularization. Patients who have STEMI require urgent reperfusion either with thrombolytic agents or primary angioplasty. Follow-ing a diagnosis of CHD, patients should undergo intense coronary risk-fac-tor modification to reduce the risk of future events.

Concomitant use of nitrates, calcium channel blockers, and beta blockers for optimal antianginal therapy

Despite the introduction of new mechanical techniques for revascularization, pharmacologic therapy continues to be the mainstay of antianginal therapy. The conventional antianginal medications, which include nitrates, beta blockers, and calcium channel blockers, act to correct the imbalance between myocardial supply and demand by increasing coronary blood flow, reducing myocardial oxygen requirements, or both. All three are appropriate for the management of angina caused by a fixed coronary obstruction, but nitrates and calcium channel blockers, which not only reduce demand but also increase supply, are preferred in cases of angina believed to involve a significant increase in vasomotor tone. Because of the different yet complementary mechanisms of action of the three classes of anti-ischemic drugs, use of these agents in combination is a rational approach to the treatment of angina unresponsive to monotherapy. Such combinations have been shown to enhance the therapeutic response achieved with single-agent therapy. In addition, the pharmacologic action of one of the components of the combination regimen may serve to offset side effects typically associated with the other.

Effects of benazepril and metoprolol OROS alone and in combination on myocardial ischemia in patients with chronic stable angina

The efficacy of benazepril, metoprolol OROS and their combination was evaluated in 29 patients (42 to 74 years of age) with chronic stable angina and documented coronary artery disease in a placebo-controlled, double-blind, crossover trial using serial quantitated exercise testing and ambulatory electrocardiographic (ECG) monitoring. The mean (+/- SEM) exercise time was 8.5 +/- 0.7 min with placebo, 8.3 +/- 0.6 min (95% confidence interval [CI]-1.06 to 0.54) with benazepril, 9.4 +/- 0.5 min (95% CI -0.32 to 2.14) with metoprolol OROS and 9.6 +/- 0.5 min (95% CI -0.25 to 2.47) with the combination of benazepril and metoprolol OROS. The mean exercise time to the development of 1 mm ST segment depression was prolonged from 6.0 +/- 0.6 min with placebo to 6.3 +/- 0.6 min (95% CI -0.93 to 1.45) with benazepril, 7.9 +/- 0.5 min (95% CI 0.83 to 3.0) with metoprolol OROS and 8.1 +/- 0.6 min (95% CI 0.88 to 3.29) with the combination of benazepril and metoprolol OROS. Benazepril did not alter the rest or maximal heart rate, whereas metoprolol OROS alone and in combination significantly lowered the heart rate at rest and during maximal exercise. Systolic blood pressure at rest was nonsignificantly reduced, whereas diastolic blood pressure was lowered significantly by all treatments in comparison with placebo. At maximal exercise, only metoprolol OROS, whether given alone or in combination with benazepril, was able to blunt significantly systolic blood pressure and rate-pressure product.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium-channel blockers in acute myocardial infarction

The calcium-channel blockers are useful in treating a variety of cardiovascular disorders. Due to their antiischemic and spasmolytic properties, these agents have been studied in the prophylaxis and treatment of acute myocardial infarction. This article reviews this application with respect to reduction of mortality, infarct size, and reinfarction rate. Of the agents currently available for clinical use, nifedipine has been studied most extensively. This agent shows no beneficial effects in this setting and its use may in fact be harmful. Of the few trials that have been conducted with verapamil, none have shown decreased mortality. Verapamil may reduce infarct size although further confirmation is required. Diltiazem is the only agent that has been shown to have short- and long-term benefits in the patient with acute myocardial infarction. Proper patient selection is of utmost importance in ensuring successful therapy. In particular, those patients with non-Q-wave infarctions and/or normal left ventricular function can be expected to derive the most benefit in terms of reducing mortality and reinfarction rate associated with the acute event.

Out-patient use of beta-blocking agents--prescribing preferences of physicians in training

Beta-blocking agents are among the most frequently prescribed medications. To investigate the factors that influence their use we analysed the practices of 25 medical residents who provided longitudinal care in the out-patient clinics of a teaching hospital. A computer-based audit identified the 349 patients treated with one of four beta-blocking agents during a 4-month period. The most frequently prescribed was atenolol (48%), followed by metoprolol (28%), propranolol (20%), and nadolol (4%). Ease of use and compliance and continuation of a beta-blocker prescribed by a previous physician emerged as the most influential factors. In contrast, cost of drugs, manufacturers' promotions and advertisements had no significant influence on beta-blocker selection.

Pharmacologic and pharmacokinetic comparison of antianginal agents

Calcium channel blockers, nitrates, and beta blockers are the primary agents used for the treatment of angina. Calcium has a central role in excitation-contraction, action potential generation, and ischemic cell death. The three currently available calcium antagonists are nifedipine, verapamil, and diltiazem. Second-generation agents are in development, and a classification system of calcium channel blockers is used to place the currently available agents and those on the horizon in perspective. Nitrate pharmacology and pharmacodynamics are possibly related to nitrate tolerance; however, this is a matter of some controversy. The beta blockers are all equally effective in the treatment of angina; therefore, drug selection is based on ancillary properties.