Anti-Anginal Drugs

• Angina Pectoris refers to chest pain resulting from myocardial ischemia due to reduced blood flow to the heart muscle.
• Anti-Anginal Drugs aim to relieve and prevent angina by improving myocardial oxygen supply or reducing demand.

Major Classes of Anti-Anginal Drugs

1. Nitrates

• Examples: Nitroglycerin, Isosorbide Mononitrate, Isosorbide Dinitrate
• MOA: Donate nitric oxide (NO), causing vasodilation of veins (reducing preload) and arteries (reducing afterload).
• Benefits: Provide rapid relief of acute angina and prevent anginal episodes.
• Side Effects: Headache, hypotension, reflex tachycardia, tolerance with continuous use.
• Considerations: Implement a nitrate-free interval to prevent tolerance development.

2. Beta-Blockers

• Examples: Metoprolol, Atenolol, Propranolol
• MOA: Decrease heart rate, contractility, and myocardial oxygen demand by blocking β-adrenergic receptors.
• Benefits: Prevent angina and improve survival in patients with coronary artery disease.
• Side Effects: Bradycardia, fatigue, bronchoconstriction.
• Considerations: Use with caution in patients with asthma or diabetes.

3. Calcium Channel Blockers

• Examples: Diltiazem, Verapamil, Amlodipine, Nifedipine
• Subclasses:

1. Dihydropyridines

   • Examples: Amlodipine, Nifedipine
   • MOA: Predominantly vasodilatory, reducing afterload by blocking L-type calcium channels in vascular smooth muscle.
   • Benefits: Prevent angina and treat hypertension.
   • Side Effects: Peripheral edema, flushing.

2. Non-Dihydropyridines

   • Examples: Diltiazem, Verapamil
   • MOA: Reduce heart rate and contractility by blocking calcium channels in the heart.
   • Benefits: Prevent angina and control arrhythmias.
   • Side Effects: Bradycardia, constipation (verapamil).

4. Ranolazine

• Example: Ranexa
• MOA: Inhibits the late phase of the inward sodium current in cardiac myocytes, improving myocardial relaxation and reducing diastolic tension.
• Benefits: Relieves chronic angina without significant hemodynamic effects.
• Side Effects: Dizziness, constipation, headache.

5. Nicorandil

• MOA: Acts both as a nitrate, donating nitric oxide (NO) for vasodilation, and as a potassium channel opener, causing additional vasodilation.
• Benefits: Prevents and relieves angina.
• Side Effects: Headache, hypotension, flushing.

6. Enhancers of Coronary Blood Flow

• Examples: Trimetazidine
• MOA: Shifts myocardial metabolism from fatty acid oxidation to glucose oxidation, improving metabolic efficiency under ischemic conditions.
• Benefits: Improves anginal symptoms and enhances myocardial metabolism.
• Side Effects: Nausea, dizziness.

Clinical Considerations:

• Combination Therapy: Often used to maximize symptom relief and minimize side effects.
• Lifestyle Modifications: Essential for long-term management (e.g., smoking cessation, diet, exercise).
• Patient Education: Importance of adherence, recognizing side effects, and proper use of medications (e.g., nitrates).

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