I have an old yellow orange capsule in an Rx bottle written to me that states that it is Cephalexin 500MG, which I know to be an antibiotic. However, I m not sure if that capsule really is Cephalexin. I need to know what the capsule I have really is. Description: yellow-orange with Mylan 4010 imprinted on it. I ve attempted looking it up in my Nursing Handbook, but am unable to find it. I know the colors in the book are not true, but I can t find anything with those markings on it. Can you help, or do I need to simply ask my pharmacist?