As others have pointed out, getting no sleep at all is really not good.
If you can't sleep, get up for a bit and do something, then possibly have a shower if you can. If you can then even get an hour of sleep before you go to work, it will help a lot.
I remember a friend back when I was at University thinking he would do better if he just stayed up all night, revised and then went to his exam which was after lunch the next day. He was on coffee constantly and in the end it did him far worse than if he had just got some sleep.
I think it's also important to look at why you aren't sleeping.
It's understandable if it's nervousness for something the following day, but there are people who seem to have trouble sleeping every night. Another friend of mine used to complain she could never sleep, I then pointed out that she was drinking seven cups of tea a day, so what did she expect? It was especially stupid given that she is a Pharmacist.