Dilaudid/Hydromorphone's bioavailability varies widely among individuals (10%-65%) and is metabolized somewhat differently than other opioids (partly via the UGT1A3 enzyme).
I tried Hydromorphone IR and it didn't have any effect on me... presumably I'm towards the lower range. I don't know if the ER mechanism alters the level of bioavailability, but I suspect that its benefits will also vary widely from individual to individual.
Like you, I'm starting a new long-acting agent this weekend: moving from Ultram ER 300mg to Kadian.
Hope it goes well for you.
BTW, if curious, I got the above data from:
C4-T4 Scoliosis (disk degeneration, stenosis, narrowed neuroforamen, bone spurs), RT hip and SI joint damage from car accident. Also, pectus excavatum, supraventricular tacycardia and mitral valve prolapse syndrome.
Current meds: Ultram ER 300mg daily, breakthrough - hydrocodone 10-15mg, or oxycodone 5-7.5mg. .25-.5mg ativan as needed for sleep, Verapamil 240mg SR (for tachycardia). [/gray