Is isosorbide dinitrate (Isordil) or beta blockers more effective for treating stable angina?

From the Guidelines

For patients with stable angina, beta blockers are the preferred first-line therapy over isosorbide dinitrate due to their ability to reduce myocardial oxygen demand and improve survival. According to the American College of Physicians guideline 1, beta blockers, such as metoprolol or atenolol, are recommended for patients with symptomatic chronic stable angina to prevent myocardial infarction (MI) or death and to reduce symptoms. The guideline suggests that calcium antagonists (long-acting) and long-acting nitrates, like isosorbide dinitrate, may be substituted for beta blockers if they lead to unacceptable side effects.

Some key points to consider when choosing between beta blockers and isosorbide dinitrate for stable angina include:

• Beta blockers reduce myocardial oxygen demand by decreasing heart rate, blood pressure, and contractility, effectively preventing angina episodes and improving survival in patients with coronary artery disease.
• Isosorbide dinitrate works by dilating blood vessels and reducing preload, which can be effective for symptom relief but does not offer the same mortality benefit as beta blockers.
• Isosorbide dinitrate is typically used as an add-on therapy when beta blockers alone are insufficient or as an alternative when beta blockers are contraindicated, such as in severe bradycardia, heart block, or severe asthma.

The American College of Physicians guideline 1 recommends the following agents for patients with symptomatic chronic stable angina:

• Aspirin or clopidogrel to prevent MI or death
• Beta blockers, such as metoprolol or atenolol, to prevent MI or death and to reduce symptoms
• Low-density lipoprotein cholesterol-lowering therapy with a statin to prevent MI or death
• ACE inhibitor to prevent MI or death
• Sublingual nitroglycerin or nitroglycerin spray for the immediate relief of angina
• Calcium antagonists (long-acting) or long-acting nitrates, like isosorbide dinitrate, when beta blockers are clearly contraindicated or in combination with beta blockers when beta blockers alone are unsuccessful.

From the Research

Treatment Options for Stable Angina

• Isosorbide dinitrate and beta blockers are both used to treat stable angina, but the choice of treatment depends on various factors, including the patient's medical history and contraindications 2.
• Beta blockers are recommended as initial therapy for stable angina, as they reduce morbidity and mortality, and eliminate angina with minimal adverse effects 2, 3.
• Isosorbide dinitrate is considered a third-line therapy, as it requires a nitrate-free interval to avoid developing tolerance 2.

Efficacy of Beta Blockers

• Beta blockers have been shown to be effective in reducing the frequency of anginal attacks and improving exercise capacity in patients with stable angina 4.
• However, the impact of beta blockers on mortality in stable angina is unclear, with some studies suggesting no statistically significant benefit 3.
• Cardioselective beta blockers may have a greater improvement in mortality compared to non-cardioselective beta blockers, but further study is needed 3.

Comparison of Treatment Options

• Antianginal drugs, including beta blockers, calcium channel blockers, and nitrates, are equally effective in treating angina pectoris, but none reduce mortality or the risk of myocardial infarction 5, 6.
• The choice of treatment should be individualized based on the patient's specific needs and medical history, and may involve a combination of lifestyle changes, antianginal drugs, and other therapies 6, 4.