I actually did this once when I was fresh out of nursing school
. Nothing happened, the pt was fine. And when I talked to my pharmacist about it he said that the reason they say not to mix is because there is not enough research out there that proves its ok to mix. Some cases sugars went crazy others didnt, but it wasnt conclusive. Of course when I told the MD what I had done, he looked at me like I had snakes in my ears, he didnt care, nor did he have any idea what I was talking about.
Long story short...dont do it, its considered an error on our part, but dont panic if it accidentally happens.
Cheesy, but I remember that Lantus is Lonely and therefor goes in a syringe all by itself!