How is the 50 mg naltrexone supposed to be taken?

As you probably know, naltrexone is used to primarily block one from feeling the opiate "high" (also used for alcohol dependence).
25 - 50 mg is a standard starting dose, but the actual dosing schedule can vary. It's important to talk to her doctor as taking it at a specific dose (not always 50mg, day in and day out) is important.
Also, naltroxone is usually used in conjunction with a recovery program and counseling.
I truly feel for your daughter. Chronic pain and opiates are a very vicious cycle. Please remind her that anyone who takes pain meds (even legitimately) for a length on time will become dependant on them.
It's the nature of the beast.
I hope this helped. Again, please check with the doctor for clear instructions. If it does not seem to be working, get a second opinion as there are other ways to dose. Counseling, counseling, counseling.
hang in there! And kudos for helping your daughter. opiate addiction is so painful.