pellicle
Professional Dingbat, Guru and Merkintologist
in Australia the system is quite clear on what I'll say next: do not swing brands. Pick a brand and stay with it exclusively. In Australia the prescription is brand specific and no brand substitution is permittedWell, this caused me to wonder, so I looked at Drugs.com. https://www.drugs.com/imprints.php?drugname=warfarin&maxrows=18
I will try to follow Protimenow's suggestion and stick with 1 manufacturer. A particular "color" gets implemented in various ways be various manufacturers. Plus they vary the labeling and the shape.
https://www.amsj.org/archives/4762
As a self tester you'll note the INR shift and you'll then be able to lean into that as needed (should you do so).
Best Wishes