Medical providers commonly encounter patients in the emergency department who state they are anticoagulated with warfarin, but they have no idea what dose they are taking. “I know that I take two pills of warfarin daily.” Dosing becomes critically important especially when continuing their medication as an inpatient, refilling their medications, or adjusting their outpatient dose because of an inappropriately high or low INR level. How can you determine the patient’s warfarin dose?

Trick of the Trade

Ask about the color of his/her warfarin tablets

In the United States, manufacturers of both brand and generic warfarin have agreed to make each strength a consistent color. While the colors do NOT change, the shape and shade may vary.

Helpful Mnemonics

To aid your memory recall of the colors, you can use this mnemonic

“Please Let Granny Brown Bring Peaches To Your Wedding”

Alternatively, @scepticalemdoc from Queensland, Australia offered an EM-related mnemonic:

“Probably Leaves Granny Bleeding Bloody Profusely, Thank You Warfarin”

Safety Considerations

While this color-coding scheme holds true for warfarin dispensed in the United States, it may not apply in other countries as pointed out by @laurajanebroad. Also be cautious of patients with deuteranopia (color-blindness), who may mistakenly report the wrong tablet color.

Another trick using colors

Color-coded eye drop bottles

Author information

Samantha Boartfield, PharmD

PGY-1 Pharmacy Practice Resident
Banner University Medical Center – Phoenix

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