Can Amlong (amlodipine) be taken twice daily?

Amlodipine Should Be Taken Once Daily, Not Twice Daily

Amlodipine (Amlong) is specifically designed and approved for once-daily administration only, and dividing the dose into twice-daily administration provides no clinical benefit. 1, 2

FDA-Approved Dosing

The FDA label explicitly states that amlodipine should be administered once daily for all indications 2:

• Initial dose for hypertension: 5 mg once daily 2
• Maximum dose: 10 mg once daily 2
• Angina dosing: 5-10 mg once daily 2
• Pediatric dosing (ages 6-17): 2.5-5 mg once daily 2

Pharmacokinetic Rationale

The once-daily dosing is supported by amlodipine's unique pharmacokinetic properties 1, 3:

• Elimination half-life: 30-50 hours, which is exceptionally long for a calcium channel blocker 1
• Gradual absorption: Peak plasma levels occur 6-12 hours after administration 3
• Low clearance: Maintains effective plasma levels throughout a 24-hour period with once-daily dosing 3
• Steady state: Achieved after 7-9 doses with once-daily administration 3

Evidence Against Twice-Daily Dosing

A direct comparison study definitively showed that dividing amlodipine 10 mg into twice-daily doses offers no advantage 4:

• No improvement in 24-hour blood pressure control: Mean 24-hour BP was 129.7/80.1 mmHg with twice-daily vs 130.5/80.1 mmHg with once-daily (not significant) 4
• No increase in trough drug levels: 22.37 ng/mL vs 20.57 ng/mL (not significant) 4
• No reduction in arterial stiffness: CAVI values were identical between regimens 4
• No benefit for daytime, nighttime, or early morning BP: All time periods showed equivalent control 4

Clinical Guideline Consensus

Major cardiovascular societies uniformly recommend once-daily administration 5, 1, 6:

• The American College of Cardiology specifies once-daily dosing at 2.5-10 mg for adults 1
• The American Heart Association recommends once-daily administration, with dose escalation from 5 mg to 10 mg once daily if needed after 2-6 weeks 6
• The European Society of Cardiology emphasizes that amlodipine is specifically designed for once-daily use, unlike shorter-acting calcium channel blockers 1

Common Pitfall to Avoid

Do not confuse amlodipine with shorter-acting calcium channel blockers that require multiple daily doses 5:

• Nicardipine and isradipine require 2-3 times daily dosing and are not recommended for resistant hypertension due to poor adherence 5
• Eplerenone (a mineralocorticoid receptor antagonist, not a calcium channel blocker) requires twice-daily dosing due to its shorter half-life 5

Practical Recommendation

Administer amlodipine at the most convenient time of day for the patient to maximize adherence 6. If blood pressure remains uncontrolled after 2-6 weeks at 5 mg once daily, increase to 10 mg once daily rather than splitting the dose 6, 2. If 10 mg once daily is insufficient, add a second agent (preferably an ACE inhibitor/ARB or thiazide diuretic) rather than attempting twice-daily amlodipine dosing 6.