They have a long acting dilaudid now Saucer...
When I took it with morphine ER it only lasted for 2 hours for me (the immediate one) it's a good medication but does not last.
Just my opinion/advice... but if you are taking a narcotic/opioid for a long period of time (I think it's 2 weeks +) then you should consider taking a long acting/extended with a medication for breakthrough pain.
When you read the inserts, or start reading about chronic pain, in fact it's even posted on here under the pain management sticky- you have to take the pain meds when the pain is not severe.. or they don't work well. Then you take something in between when needed. You then avoid shocking your body into pain constantly and trying to calm it down again.
My pain is a 3 when I do this. I have a spinal cord issue (damage/stretching) as well as something similar to Fibro.. I know when I wait to take the medication it just does not work correctly and gets me to a 7-8 again.
Talk to your doctors... and think about the long acting. Do your research etc. whatever is best for you.