I am feeling really conflicted about a rocephin injection I gave today..another nurse was with me but she just graduated and got her license. The doctor ordered 850mg of Rocephin. We had on hand 500mg vials and the lidocaine. She pulled two vials down. Ordered to be administered IM * 1If if you have 850mg ordered how many ml get pulled from each vial or what is the best way to administer 850mg of rocephin when you just have 500mg vials to choose from?