What are the first-line drugs for stable angina and how does treatment differ for unstable angina?

From the Guidelines

The first-line treatment for stable angina includes beta-blockers, such as metoprolol 25-100 mg twice daily or atenolol 25-100 mg daily, as the preferred initial therapy due to their benefits in reducing the risk of heart failure hospitalization and premature death 1.

Stable Angina Treatment

The treatment for stable angina focuses on reducing symptoms and preventing myocardial infarction (MI) and death.

• Beta-blockers are recommended as the first-line treatment for stable angina, unless contraindicated, due to their ability to reduce the risk of MI and death, as well as alleviate symptoms 1.
• For patients who cannot tolerate beta-blockers, alternatives such as ivabradine, oral or transcutaneous nitrates, or amlodipine may be considered to relieve angina, with the choice depending on the patient's specific conditions and preferences 1.
• All stable angina patients should also receive antiplatelet therapy, such as aspirin 81-325 mg daily, and statins for secondary prevention to reduce the risk of MI and death 1.

Unstable Angina Treatment

Unstable angina, representing an acute coronary syndrome, requires a different approach:

• Dual antiplatelet therapy, including aspirin and clopidogrel, is crucial in the management of unstable angina, along with anticoagulation and aggressive anti-ischemic therapy 1.
• Unstable angina patients typically require urgent cardiac catheterization and possible revascularization, unlike stable angina which can often be managed medically.
• The pathophysiology of unstable angina involves acute plaque rupture with thrombus formation, necessitating immediate intervention to prevent myocardial infarction.

Key Differences in Treatment Approach

The main difference in treatment between stable and unstable angina lies in the urgency and the goals of therapy:

• Stable angina management focuses on symptom relief, prevention of MI, and reduction of mortality through medical therapy and lifestyle modifications.
• Unstable angina treatment is more aggressive, aiming at immediate stabilization of the patient and prevention of MI through urgent revascularization and intensive medical therapy.

From the FDA Drug Label

The effectiveness of 5 to 10 mg/day of amlodipine in exercise-induced angina has been evaluated in 8 placebo-controlled, double-blind clinical trials of up to 6 weeks duration involving 1038 patients (684 amlodipine, 354 placebo) with chronic stable angina Amlodipine besylate tablets is indicated for the symptomatic treatment of chronic stable angina. Amlodipine besylate tablets may be used alone or in combination with other antianginal agents In patients with coronary artery disease, metoprolol can cause depression of myocardial contractility and may precipitate heart failure and cardiogenic shock. Do not abruptly discontinue metoprolol therapy in patients with coronary artery disease.

First line of drugs for stable angina:

• Amlodipine is used for the symptomatic treatment of chronic stable angina.
• Metoprolol can be used for the treatment of angina, but it should be used with caution in patients with coronary artery disease.

Difference in treatment for unstable angina:

• Unstable angina requires immediate medical attention and treatment.
• The treatment for unstable angina may involve the use of medications such as beta-blockers (e.g. metoprolol), nitrates, and antiplatelet agents.
• Amlodipine may not be the first line of treatment for unstable angina, but it can be used in combination with other medications to help manage the condition.
• The key difference in treatment between stable and unstable angina is the need for immediate medical attention and the use of more aggressive treatments, such as beta-blockers and antiplatelet agents, in unstable angina 2, 2, 3.

From the Research

Stable Angina Treatment

• The primary goal of treating stable angina is to reduce morbidity and mortality, and to eliminate angina with minimal adverse effects, allowing patients to return to normal activities 4.
• Beta-blockers are recommended as the initial therapy for stable angina, unless there are contraindications, in which case calcium antagonists should be administered 4, 5.
• Long-acting dihydropyridine and nondihydropyridine agents are generally as effective as beta-blockers in relieving angina 4.
• Long-acting nitrates are considered third-line therapy, as a nitrate-free interval is required to avoid developing tolerance 4.

Difference in Treatment for Unstable Angina

• Unstable angina requires a different treatment approach, with a focus on reducing the risk of myocardial infarction and preventing further ischemic episodes 6.
• Aspirin is an important therapeutic agent in the management of unstable angina, due to its antiplatelet effects 6.
• The combination of aspirin and vasodilators, such as heparin and beta-blockers, may be necessary to control symptoms and prevent further ischemic episodes in patients with unstable angina 6.
• Early coronary angiography and aggressive treatment may be necessary for patients who do not respond to combined therapy 6.

First Line of Drugs for Stable Angina

• Beta-blockers are considered a first-line treatment for stable angina, due to their ability to reduce heart rate and myocardial contractility, thus reducing myocardial oxygen consumption 4, 5.
• Calcium channel blockers, such as dihydropyridine calcium channel blockers, are also considered a first-line treatment option for stable angina 5.
• The choice of first-line drug may depend on the presence of comorbid conditions, such as heart failure or hypertension 5.