How do I switch a patient from propranolol (beta-blocker) 40 mg twice a day to amlodipine (calcium channel blocker)?

Switching from Propranolol 40 mg BID to Amlodipine

You should taper propranolol gradually over 1-2 weeks while simultaneously starting amlodipine at 5 mg once daily, avoiding abrupt beta-blocker discontinuation which carries significant cardiovascular risk.

Critical Safety Consideration: Never Abruptly Stop Propranolol

• Abrupt propranolol withdrawal can cause severe exacerbation of angina, myocardial infarction, ventricular arrhythmias, and rebound hypertension, with documented 50% mortality in one study 1
• Beta-blocker withdrawal is associated with a 2.7-fold increased risk of 1-year mortality compared to continuous use 1
• Prolonged small-dose propranolol administration before complete withdrawal prevents enhanced cardiac beta-adrenergic sensitivity and adverse cardiovascular events 2

Recommended Transition Protocol

Week 1-2: Overlap Period

• Start amlodipine 5 mg once daily immediately 3
• Continue propranolol 40 mg BID for the first 3-4 days 1
• After 3-4 days, reduce propranolol to 40 mg once daily for 3-4 days 1
• Then reduce to 20 mg once daily for 3-4 days 1
• Finally, reduce to 10-20 mg once daily for 3-4 days before complete discontinuation 1, 2

Rationale for Amlodipine Starting Dose

• Amlodipine 5 mg once daily is the standard initial dose for hypertension with proven efficacy 3
• Early dose escalation to 10 mg provides no advantage; dose increases should not be considered until after 6 weeks at 5 mg daily 4
• Amlodipine has a long half-life (48-64 hours) allowing once-daily dosing with sustained 24-hour blood pressure control 5, 6

Monitoring During Transition

Days 1-7

• Check blood pressure and heart rate daily if possible, or at minimum every 2-3 days 1
• Watch for rebound hypertension (systolic BP >20 mmHg above baseline) 1, 2
• Monitor for rebound tachycardia (heart rate >110 bpm) 1, 2
• Assess for new or worsening anginal symptoms 1

Days 8-14

• Continue monitoring blood pressure and heart rate every 2-3 days 1
• Watch for amlodipine-related side effects: peripheral edema, headache, dizziness, flushing 3
• Ensure heart rate remains >50 bpm and systolic BP >100 mmHg 1

Week 3-6

• Blood pressure should be checked at clinic visits 3
• Target blood pressure reduction of at least 20/10 mmHg, ideally to <140/90 mmHg 1
• Do not increase amlodipine dose until after 6 weeks at 5 mg daily 4

Expected Blood Pressure Response

• Amlodipine 5 mg produces mean reductions of approximately 11-13/10-12 mmHg in mild-to-moderate hypertension 6
• Blood pressure decreases steadily until the end of week 6 of amlodipine treatment 4
• Response rate (diastolic BP ≤90 mmHg) is approximately 61-84% with amlodipine 5-10 mg daily 4, 6
• Amlodipine maintains blood pressure <140/90 mmHg throughout the 24-hour dosing interval 6

Contraindications to Check Before Starting Amlodipine

• Severe aortic stenosis (relative contraindication) 3
• Known hypersensitivity to dihydropyridine calcium channel blockers 3
• Decompensated heart failure (use with caution) 3

Common Pitfalls to Avoid

• Never stop propranolol abruptly - this is the most critical error with potentially fatal consequences 1, 2
• Do not increase amlodipine to 10 mg before 6 weeks unless blood pressure remains severely elevated 4
• Do not combine amlodipine with non-dihydropyridine calcium channel blockers (diltiazem, verapamil) due to additive cardiac depression 1, 7
• Do not assume all beta-blockers can be tapered the same way - propranolol specifically requires gradual tapering 1, 2

When to Hold or Adjust Doses

• Hold amlodipine if systolic BP <100 mmHg with symptoms (dizziness, lightheadedness) 1
• Temporarily return to previous propranolol dose if patient develops chest pain, palpitations, or significant tachycardia during taper 1, 2
• If severe rebound hypertension occurs, resume propranolol at previous dose and taper more slowly 1, 2

Dose Escalation After 6 Weeks (If Needed)

• If blood pressure remains >140/90 mmHg after 6 weeks on amlodipine 5 mg daily, increase to 10 mg once daily 3, 4
• Maximum dose is 10 mg once daily for most patients 3
• Elderly patients may require lower doses due to altered pharmacokinetics 5