"Epinephrine solution deteriorates rapidly on exposure to air or light, turning pink from oxidation to adrenochrome and brown from the formation of melanin. Replace epinephrine injection, USP if the epinephrine solution appears discolored (pinkish or brown color), cloudy, or contains particles."
It's also in the Epinephrine injection. Scroll down to table of contents, go to section 11 and read the 2nd to last paragraph.
https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=e13f05f1-7d21-49bb-b8d5-24bf9301c3d7#section-10
"Epinephrine solution deteriorates rapidly on exposure to air or light, turning pink from oxidation to adrenochrome and brown from the formation of melanin. Replace epinephrine injection, USP if the epinephrine solution appears discolored (pinkish or brown color), cloudy, or contains particles."