What is the recommended use and dosage of Dihydropyridine (DHP) calcium blockers, such as amlodipine (Norvasc), in the treatment of hypertension and angina?

Dihydropyridine Calcium Channel Blockers in Hypertension and Angina

Dihydropyridine calcium channel blockers (DHPs) are recommended as first-line therapy for hypertension with angina, particularly when added to beta blockers in patients with stable ischemic heart disease (SIHD) who have persistent angina despite beta blocker therapy. 1

Indications and Clinical Use

Hypertension Management

• DHPs effectively reduce blood pressure by causing peripheral vasodilation
• Recommended for:
  • Patients with hypertension and SIHD, particularly with angina 1
  • Add-on therapy when BP goal (<130/80 mmHg) is not met with first-line agents 1

Angina Management

• DHPs are particularly effective for:
  • Stable angina when combined with beta blockers 1
  • Vasospastic angina as first-line therapy 2
  • Chronic stable angina (both effort-induced and vasospastic) 3

Specific Agents and Dosing

Amlodipine (Norvasc)

• Initial dose: 5 mg once daily 3
• Maximum dose: 10 mg once daily 3
• Special populations:
  • Elderly, fragile patients, or those with hepatic insufficiency: Start with 2.5 mg once daily 3
  • For angina: 5-10 mg once daily (most patients require 10 mg for adequate effect) 3
• Titration: Wait 7-14 days between dose adjustments 3
• Pharmacokinetics: Long half-life (40-60 hours) allows for once-daily dosing with minimal fluctuation (20-25%) between doses 4

Other DHPs (from guidelines)

• Felodipine: 2.5-10 mg once daily 1
• Isradipine: 5-10 mg twice daily 1
• Nicardipine SR: 60-120 mg twice daily 1
• Nifedipine LA: 30-90 mg once daily 1
• Nisoldipine: 17-34 mg once daily 1

Treatment Algorithm

1. For hypertension with SIHD:

   • First-line: Beta blockers, ACE inhibitors, or ARBs (for compelling indications like previous MI or stable angina) 1
   • If BP goal (<130/80 mmHg) not met OR if angina persists: Add dihydropyridine CCB 1
   • If still not controlled: Add thiazide diuretics and/or mineralocorticoid receptor antagonists 1

2. For vasospastic angina:

   • First-line: DHPs (e.g., nifedipine up to 120 mg/day or amlodipine 10 mg daily) 2
   • If symptoms persist: Increase dose gradually or add long-acting nitrates 2

Clinical Pearls and Caveats

• DHPs are preferred over non-dihydropyridine CCBs (diltiazem, verapamil) when combined with beta blockers to avoid excessive bradycardia or heart block 1
• DHPs should be avoided in patients with heart failure with reduced ejection fraction (HFrEF) 1
• Common side effects include peripheral edema (more common in women), headache, dizziness, and flushing 1, 5
• Unlike some other CCBs, amlodipine has not shown development of tolerance in long-term trials 3, 6
• Once-daily amlodipine provides equivalent efficacy to twice-daily nifedipine retard with potentially better compliance 7
• Early dose titration of amlodipine (before 6 weeks) may not provide additional benefit in hypertension management 8
• Gingival hyperplasia is a rare side effect that may occur with long-term use 5

Monitoring

• Monitor blood pressure response at regular intervals
• Assess for peripheral edema, particularly with higher doses
• Evaluate for symptom relief in patients with angina
• No specific laboratory monitoring required for DHPs

By following these evidence-based recommendations, dihydropyridine calcium channel blockers can effectively manage hypertension and angina, particularly when used as part of a comprehensive treatment approach targeting blood pressure control and symptom relief.