From the Guidelines
Calcium channel blockers (CCBs) and nitrates do not reduce mortality in acute myocardial infarction (MI) because they fail to address the underlying pathophysiology of the condition, as evidenced by a meta-analysis of 17 trials involving calcium antagonists early in the course of STEMI showing no beneficial effect on death or reinfarction 1.
Pathophysiology and Mechanism
The primary reason for this lack of mortality benefit is that CCBs and nitrates do not directly impact the thrombotic occlusion causing the infarction. CCBs like diltiazem, verapamil, and nifedipine may even be harmful in certain acute MI settings by causing reflex tachycardia or excessive vasodilation, potentially worsening ischemia by decreasing coronary perfusion pressure 1. Similarly, nitrates such as nitroglycerin or isosorbide dinitrate primarily work by dilating coronary vessels and reducing preload, which helps with angina symptoms but doesn't significantly impact the thrombotic occlusion 1.
Comparison with Effective Therapies
In contrast, therapies that have been proven to reduce mortality in acute MI include reperfusion strategies (thrombolytics or primary PCI), antiplatelet agents (aspirin, P2Y12 inhibitors), anticoagulants, beta-blockers, ACE inhibitors, and statins. These interventions directly address thrombosis, limit infarct size, prevent remodeling, or reduce recurrent events, making them more effective at improving survival outcomes in acute MI patients 1.
Clinical Implications
The routine use of calcium antagonists in the acute phase of STEMI is not indicated, as they have shown no beneficial effect on death or reinfarction 1. However, in patients with contraindications to beta-blockers, particularly in the presence of obstructive airway disease, calcium antagonists are a reasonable option for patients without heart failure or impaired LV function 1. Nitrates may still be used for symptomatic relief of angina or as a vasodilator in patients with MI associated with left ventricular failure, but they should not be relied upon to reduce mortality 1.
From the FDA Drug Label
The benefits of sublingual nitroglycerin in patients with acute myocardial infarction or congestive heart failure have not been established. The FDA drug label does not answer the question.
From the Research
Calcium Channel Blockers (CCBs) and Nitrates in Acute Myocardial Infarction (MI)
- CCBs do not reduce mortality in patients with acute MI 2, 3
- Nitrates do not reduce mortality in patients with acute coronary syndromes, including acute MI 4
- The use of CCBs and nitrates in acute MI is not recommended due to lack of mortality benefit 5, 6
Mechanisms and Effects
- CCBs that increase heart rate (e.g. dihydropyridines) may increase the risk of death and reinfarction 2
- CCBs that reduce heart rate (verapamil and diltiazem) may have a neutral effect on mortality but reduce reinfarction rates 2, 3
- Nitrates may have a place in the acute therapy of myocardial infarction, but their use is limited due to potential side effects 4, 5