I'm a first year nursing student. I'm confused about a medication label given on a drug calculation practice test. Can someone please clear this up for me? The label given in the question reads: "Diphenhydramine HCL Inj 50mg/ml 1ml in a 2ml Single Dose vial" The order is for 50mg IV. Does this mean that the vial contains only 1ml or 2ml? How many milligrams would would be given if I administered the entire vial? Thanks in advance