Antianginal Drugs Notes
Definition and Purpose:
Antianginal drugs are medications used to prevent or treat angina pectoris
They work by improving the balance between myocardial oxygen supply and demand
Main Classes of Antianginal Drugs:
a) Nitrates
b) Beta-blockers
c) Calcium channel blockers
d) Potassium channel openers
e) Other agents (e.g., ranolazine)
Nitrates:
Mechanism: Vasodilation, reducing preload and afterload
Examples: Nitroglycerin, isosorbide mononitrate, isosorbide dinitrate
Uses: Acute angina relief and prophylaxis
Key points:
Rapid onset of action (especially sublingual nitroglycerin)
Risk of tolerance with continuous use
Common side effects: headache, hypotension
Beta-blockers:
Mechanism: Reduce heart rate and myocardial oxygen demand
Examples: Metoprolol, atenolol, propranolol
Uses: Angina prevention and treatment
Key points:
Effective for both stable and unstable angina
Contraindications: severe asthma, uncontrolled heart failure
Side effects: fatigue, cold extremities, sexual dysfunction
Calcium Channel Blockers:
Mechanism: Vasodilation and reduction of myocardial contractility
Examples: Amlodipine, diltiazem, verapamil
Uses: Angina prevention, especially in patients intolerant to beta-blockers
Key points:
Dihydropyridines (e.g., amlodipine) primarily cause vasodilation
Non-dihydropyridines (e.g., verapamil) also slow heart rate
Side effects: peripheral edema, constipation, headache
Potassium Channel Openers:
Example: Nicorandil
Mechanism: Vasodilation without affecting heart rate or contractility
Uses: Additional option for chronic stable angina
Key points:
Not widely available in all countries
Can cause headaches and dizziness
Other Agents:
Ranolazine:
Mechanism: Inhibits late sodium current in cardiac cells
Uses: Chronic stable angina
Advantages: Minimal effects on heart rate and blood pressure
Combination Therapy:
Often provides better symptom control than monotherapy
Common combinations:
Nitrate + Beta-blocker
Nitrate + Calcium channel blocker
Beta-blocker + Calcium channel blocker (with caution)
Clinical Considerations:
Individual patient factors (comorbidities, contraindications)
Monitoring for efficacy and side effects
Patient education on proper use and potential adverse effects
Regular follow-up and adjustment of therapy as needed
Non-pharmacological Approaches:
Lifestyle modifications (smoking cessation, exercise, diet)
Stress reduction techniques
Cardiac rehabilitation programs
Emergency Management:
Sublingual nitroglycerin for acute angina attacks
Patient education on when to seek emergency care
Remember: This is a general overview. Always consult current guidelines and prescribing information for detailed and up-to-date information on antianginal drug therapy.