What is the use of Amlodipine (calcium channel blocker) in treating hypertension and coronary artery disease?

Amlodipine Besylate in Hypertension and Coronary Artery Disease

Amlodipine besylate is a first-line dihydropyridine calcium channel blocker effective for treating both hypertension and coronary artery disease, providing consistent 24-hour blood pressure control with once-daily dosing and cardiovascular event reduction. 1

Mechanism and Indications

Amlodipine works by relaxing blood vessels, allowing blood to flow more easily and reducing blood pressure. It is specifically indicated for:

• Hypertension (as monotherapy or in combination)
• Angina (both chronic stable angina and vasospastic/Prinzmetal's angina)
• Coronary artery disease with or without hypertension 2

Efficacy in Hypertension

• Produces significant reductions in both systolic and diastolic blood pressure, averaging 12-13/6-7 mmHg 1
• Particularly effective for isolated systolic hypertension in elderly patients 1
• Provides consistent 24-hour blood pressure control with once-daily dosing 3
• Maintains normal circadian blood pressure patterns without affecting heart rate 3

Efficacy in Coronary Artery Disease

• Reduces frequency and severity of angina episodes 2, 4
• Increases exercise duration and decreases exercise-induced ST segment depression in patients with coronary artery disease 4
• Associated with fewer hospitalizations for unstable angina and revascularization 5
• Slows progression of carotid artery atherosclerosis as measured by intimal-medial thickness 5

Dosing Guidelines

• Starting dose: 2.5-5 mg once daily
• Maintenance dose: 5-10 mg once daily
• Elderly or hepatic impairment: Start with 2.5 mg once daily
• Can be taken with or without food 2, 1

Use in Special Populations

Hypertension with Coronary Artery Disease

• Amlodipine can be safely used in patients with stable coronary artery disease 6
• Can be combined with beta-blockers for enhanced efficacy in patients with angina 1
• Target BP is <140/90 mmHg, but <130/80 mmHg may be considered in some individuals with CAD 6

Heart Failure

• Unlike non-dihydropyridine CCBs (verapamil, diltiazem), amlodipine can be safely used in patients with heart failure due to systolic dysfunction 6, 1
• The dihydropyridine CCB amlodipine appeared to be safe in patients with severe systolic heart failure in clinical trials 6

Combination Therapy

Amlodipine works well in combination with:

1. ACE inhibitors or ARBs - particularly effective combination with synergistic effects 1, 7

   • Fixed combination of enalapril and amlodipine is effective in normalizing BP in patients with CAD and hypertension 7

2. Beta-blockers - for patients with angina or post-MI 6

3. Thiazide diuretics - for enhanced BP control 6

Advantages Over Other Calcium Channel Blockers

• Unlike non-dihydropyridine CCBs (verapamil and diltiazem), amlodipine can be safely used in patients with heart failure with reduced ejection fraction 6
• Provides 24-hour coverage with once-daily dosing due to long half-life 3
• Does not negatively affect heart rate or cardiac conduction 3

Common Side Effects

• Peripheral edema (dose-related, more common in women)
• Flushing
• Headache
• Dizziness
• Fatigue 2

Important Considerations

• When initiating therapy for hypertension with CAD, the BP should be lowered gradually, especially in patients with elevated diastolic BP and evidence of myocardial ischemia 6
• In older hypertensive individuals with wide pulse pressures, monitor for very low diastolic BP values (<60 mmHg) which could compromise coronary perfusion 6
• Avoid non-dihydropyridine CCBs (verapamil, diltiazem) in patients with heart failure with reduced ejection fraction 6

Treatment Algorithm for Hypertension with CAD

1. First-line therapy:

   • Beta-blocker (if post-MI or with angina) plus
   • ACE inhibitor/ARB (especially with diabetes, CKD, or LV dysfunction) plus
   • Thiazide or thiazide-like diuretic 6

2. If BP remains uncontrolled or angina persists:

   • Add amlodipine (5-10 mg daily) 6, 1

3. If beta-blockers are contraindicated:

   • Amlodipine can be used as first-line therapy 6, 8

4. Target BP:

   • <140/90 mmHg for most patients
   • <130/80 mmHg may be considered in selected high-risk patients 6

Amlodipine has strong evidence for cardiovascular event reduction and should be considered a first-line agent for hypertension, particularly in patients with concomitant coronary artery disease 8.