Heart & blood pressure
Anticoagulant
Warfarin
Also known as: Coumadin, Jantoven
Best time
Evening
- 17:00–20:00
Often taken in the evening so dose changes can be made the same day after a morning blood test.
Moderate evidence
Supported by studies and drug pharmacology, but guidance varies between sources.
Why this time works
Warfarin's effect builds slowly, so the hour itself matters less than consistency. Evening dosing is a practical convention: an INR blood test in the morning lets the clinic adjust that evening's dose without delay.
Body rhythm involved
Clotting factors show modest daily variation; consistency is key.