Should the amlodipine dose be increased from 5 mg twice daily to a total of 10 mg daily?

Amlodipine Dosing Correction Required

Your patient is currently receiving an incorrect dosing regimen of amlodipine 5 mg twice daily (total 10 mg/day split), which should be immediately changed to 10 mg once daily, as amlodipine is specifically designed and approved for once-daily administration only. 1, 2

Critical Dosing Error

The current regimen of 5 mg twice daily represents a fundamental misunderstanding of amlodipine pharmacology:

• Amlodipine has an exceptionally long half-life of 30-50 hours, which supports once-daily dosing exclusively 1
• The FDA-approved dosing is 5-10 mg once daily for adults, with no provision for twice-daily administration 2
• The American College of Cardiology and European Society of Cardiology explicitly state that amlodipine is designed and approved for once-daily administration only 1

Correct Dosing Algorithm

Step 1: Assess Current Blood Pressure Control

Before making any dose adjustment, determine if blood pressure is adequately controlled:

• Target BP is <130/80 mmHg for most adults with hypertension 3
• Confirm inadequate control with home BP monitoring (≥135/85 mmHg) or 24-hour ambulatory monitoring (≥130/80 mmHg) before escalating therapy 3
• Measure BP at trough (just before the next scheduled dose) to ensure 24-hour control 3

Step 2: Check Medication Adherence

• Non-adherence is a common cause of apparent treatment failure and must be ruled out before dose escalation 3

Step 3: Determine Appropriate Dose

If BP remains above target after 2-6 weeks at 5 mg once daily:

• Increase to 10 mg once daily (the maximum approved dose) 3, 2
• Wait 7-14 days between titration steps, though more rapid titration is acceptable if clinically warranted with frequent assessment 2
• Research shows no advantage to early dose escalation; wait at least 6 weeks at 5 mg before increasing 4

Step 4: Consider Combination Therapy Instead

Rather than maximizing amlodipine to 10 mg, adding a second agent after 4-6 weeks at 5 mg may be more effective:

• Preferred combinations include amlodipine + ACE inhibitor/ARB, or amlodipine + thiazide-type diuretic 3
• Most adults with hypertension require two or more antihypertensive medications to achieve BP targets 3
• Fixed-dose single-pill combinations improve adherence 3

Immediate Action Required

Convert the current regimen from 5 mg twice daily to 10 mg once daily immediately, as the patient is already receiving the maximum daily dose but in an incorrect divided schedule 2. This change:

• Maintains the same total daily dose (10 mg)
• Corrects the dosing frequency to match FDA approval and pharmacokinetic properties 1, 2
• Can be administered at any convenient time of day to improve adherence 3

Common Pitfalls to Avoid

• Never divide amlodipine into twice-daily dosing—this is not supported by any guideline or the FDA label 1, 2
• Do not increase beyond 10 mg once daily, as this is the maximum approved dose with dose-dependent side effects (peripheral edema, headache, flushing) occurring in 10-30% of patients at this dose 3
• Avoid premature dose escalation before 6 weeks of treatment, as BP reduction continues steadily until week 6 4

Monitoring After Correction

• Schedule monthly visits until BP target is achieved 3
• Replace 30-day with 90-day refills when BP is controlled to improve adherence 3
• Monitor for dose-dependent side effects, particularly peripheral edema, which may require dose reduction or addition of an ACE inhibitor/ARB (which can reduce calcium channel blocker-induced edema) 3