I remember a terminally ill cancer patient in December 1999 who was on a hydromorphone PCA. This patient was using so much that we had to order hydromorphone power and compoud the PCA from it. Here's the amount:
250 mg/hour + 10 mg bolus prn(q 10-60 min? I did not make a note of that)
So if you "convert" to IV morphine that is about ~39,999 mg/day morphine not counting any bolus.
And that "converts" to ~119,997 mg/day oral morphine.
And that "converts" to ~79,998 mg/day oral oxycodone. Not sure how long he was on this.