Timing of Amlodipine (Norvasc) Administration
Amlodipine can be taken at any time of day—morning or bedtime—as there is no clinically significant difference in blood pressure control or cardiovascular outcomes based on dosing time. 1
Evidence Against Preferential Bedtime Dosing
The most recent and highest-quality guidelines explicitly address this question:
The 2023 and 2024 American Diabetes Association Standards of Care state that preferential use of antihypertensives at bedtime is not recommended, as subsequent large randomized trials failed to reproduce earlier findings suggesting benefit from evening dosing 1
The 2012 ADA guidelines had previously suggested potential benefit from bedtime dosing of at least one antihypertensive medication based on a single trial showing reduced cardiovascular events with median 5.4-year follow-up 1
However, this recommendation was reversed in 2023 after larger, more rigorous trials demonstrated no reproducible benefit 1
Practical Dosing Recommendations
The FDA-approved prescribing information for amlodipine states: "Take amlodipine once a day, with or without food. It may be easier to take your dose if you do it at the same time every day, such as with breakfast or dinner, or at bedtime." 2
Key practical considerations:
Consistency of timing matters more than the specific time chosen—taking amlodipine at the same time daily optimizes adherence and maintains stable blood levels 2
If a dose is missed, take it as soon as remembered, but do not take amlodipine if more than 12 hours have passed since the missed dose; instead, wait and take the next dose at the regular scheduled time 2
Amlodipine's long elimination half-life (30-50 hours) provides effective 24-hour blood pressure control regardless of morning or evening administration 3, 4, 5
Pharmacokinetic Rationale
The pharmacokinetic properties of amlodipine support flexible dosing timing:
Amlodipine maintains effective blood levels and smooth blood pressure control throughout the entire 24-hour dosing interval 3
Studies using continuous intra-arterial blood pressure monitoring demonstrate that once-daily amlodipine effectively reduces blood pressure throughout the whole 24-hour period without altering the normal circadian pattern, with significant reductions in both daytime (165/103 to 147/89 mmHg) and nighttime (137/79 to 121/69 mmHg) blood pressure 4
The drug provides smooth 24-hour blood pressure control without orthostatic hypotension when measured 24 hours after the last dose 5
Clinical Bottom Line
Choose morning or bedtime dosing based solely on patient preference and what will optimize medication adherence. There is no cardiovascular benefit to preferential bedtime dosing, and the long half-life of amlodipine ensures consistent 24-hour blood pressure reduction regardless of administration time 1, 2, 4