The best guide for IV drug compatability that I have ever used is the Thomson Micromedex computer program. It actually is easier to use than this online tutorial suggests---you basically just type in the drugs that you want to run into the same line, click once to check the compatability of the drugs, and you get a result in just seconds. We have it installed on our bedside computers at work:
As previously stated there is more to be considered than chemical compatability when running multiple drips into a single line. The possibility of giving an unintentional bolus of another drug when giving an intentional bolus of another is a big one.
For example, fentanyl and insulin are compatible but if you are giving frequent fent boluses via your pump then you run the risk of inadvertently giving an insulin bolus at the same time.
If possible I start a dedicated peripheral line for insulin gtts. It also works out better if you add those little y-port pigtails to your central catheter and attach each gtt line to a separate port. There are situations where there just are not enough lines to go around and we have to be creative---a second central line would be wonderful but there are times when we simply cannot risk trying to get a second central line due to coagulopathies, for example.
Here's a basic IV compatability chart that might be helpful:
Pharmacists? A great resource....sometimes.
I do love that Micromedex!