What is the difference between oxynorm 10 mg and oxycontin 20 mg ?!

What is the difference between oxynorm 10 mg and oxycontin 20 mg ?

the reason i"m asking is my partner has had her meds changed from the oxycontin 20mg time release to oxynorm 10mg x 2 instant relief which she has to take every 4-6 hrs , she also says the oxynorm which she takes two of 4 times a day dont seem to have the same pain killing effect ?
PS, was on two oxycontin 20 mg twice a day , and why did the doctor change it as she was fine as before ?

2 weeks ago
for the people saying 10 mg , if you read correctly my q says 10mg x 2 ........ so enough.. cheers

the main difference is oxycontin is long-term released whereas oxynorm is more immediate (and available in other forms such as liquid, injection, capsule). The element of both drugs is the same: oxycodone. So, oxycontin 20 mg twice/day is 40mg of oxycodone per day released slowly. 20mg of Oxynorm 4 times/day is 80mg of oxycodone available immediately (obviously double the effective drug). However, it may be that the time release mechanism with oxycontin was more effective for her; or, possibly the oxynorm. Drugs will have different effects for different people. Tell her to give feedback to MD because constant adjustments are typically necessary in pain control issues.