Can amlodipine (calcium channel blocker) be given on alternate days?

Amlodipine Should Not Be Given on Alternate Days

Amlodipine must be administered once daily, not on alternate days, as this is the only dosing regimen supported by clinical guidelines and pharmacokinetic evidence. 1

Standard Dosing Regimen

• The American College of Cardiology recommends amlodipine as a once-daily medication at doses of 2.5-10 mg for adults, with standard dosing being 5-10 mg once daily. 1

• Amlodipine is specifically designed and approved for once-daily administration, unlike some other calcium channel blockers that require multiple daily doses. 1

• The typical starting dose is 5 mg once daily, with simple adjustment to 10 mg if necessary for adequate blood pressure control. 2

Pharmacokinetic Rationale for Daily Dosing

The pharmacokinetic properties of amlodipine make alternate-day dosing inappropriate:

• Amlodipine has an exceptionally long elimination half-life of 30-50 hours (some studies report 40-60 hours), which supports once-daily dosing. 1, 3

• The drug accumulates to steady-state with once-daily administration over 1-1.5 weeks (seventh to ninth dose). 3, 4

• Plasma drug concentration fluctuation between doses is only 20-25% with once-daily dosing, ensuring consistent therapeutic effect throughout the 24-hour interval. 3

• Peak plasma levels occur 6-12 hours after dosing, with gradual absorption and sustained blood levels maintained throughout the dosing interval. 2, 4

Clinical Evidence Supporting Once-Daily Dosing

• Blood pressure decreases gradually over 4-8 hours after single doses and remains controlled with little fluctuation over the 24-hour dose interval during chronic once-daily dosing. 3

• Both morning and evening once-daily administration effectively reduce blood pressure throughout the 24-hour period without significantly affecting the circadian profile. 5

• Long-term studies demonstrate no tolerance development with once-daily dosing, confirming sustained efficacy. 2

Important Caveat: Confusion with Other Medications

The only context where alternate-day dosing appears in cardiovascular guidelines is for aldosterone receptor antagonists (spironolactone or eplerenone), not calcium channel blockers:

• For patients with marginal renal function (eGFR 30-49 mL/min/1.73 m²) or concerns about hyperkalemia, aldosterone antagonists may be initiated with every-other-day dosing. 6

• This alternate-day strategy does not apply to amlodipine or any calcium channel blocker. 1