If you are using a 1 gm vial of Rocephin (powder), You can reconstitute with either lidocaine (plain), sterile saline or a combination of both to make the liquid mixture. You then agitate the mixture till it is homogenized and then draw out into 2 syringes ALL of the MEDICATION. You would be giving 500mg into each IM site, usually gluteus or deltoid, or thigh, so it will be 2 injections. It is just too much once rconstituted to give into one location. Jan FNP