Yes, that is a high dose, but this is also a very painful disease.
As a chronic pain patient, (post Whipple) I use the fentanyl patch every day. It was a blessing to find something that did not require me to take a pill or to feel drowsy or groggy after I adjusted initially to the dose. I use a 50mcg patch but for the record, the higher the pain is the more pain medicine you seem to be able to tolerate without side effects. The life threatening side effects with these drugs are breathing problems. It depresses the ability to breath so over medication results in shallow breathing. (delayed, slow, shallow and could actually stop someones breathing.) So you can watch for these symptoms when they sleep. Fentanyl patches can only be used by someone that already has tolerance to opiate drugs. Your tolerance continues to grow with time even if the pain doesn't increase and soon I will probably need an upgrade in the patch even though my pain level is probably not increasing. With this form of aggressive cancer though, the pain is growing which is different from someone with a chronic ongoing problem.
My mother in law had pancreatic cancer and we were able to care for her at her home with the help of Hospice for the last weeks. Her pain level changed quickly too from my experience and the Hospice nurse was a great resource to be able to recommend a plan (with your drs approval of course) to recognize and address the pain with medication. They have been close to these patients and pain management is a huge focus of the program.
In the end, we still had difficulty controlling her pain. I am not sure she was ever completely comfortable when she was awake and even when she was asleep she cried and moaned as if the pain were still pretty great. Even in the last days when she was not really conscious and we were using a great deal of dilaudid via suppository to control her symptoms but I still think she was in pain. I did worry about over medicating her and when she died I even wondered if I had given her too much medicine even though it was ok'ed by her doctor. The nurse and the doctor assured me after her death that the medicine had no impact.
I understand why you would worry. It seems that pills are more easily to adjust until the pain seems bearable. You can gradually increase the dose until the right mix is found or the maximum recommended by the doctor is reached. The patch takes about six hours to take full effect and when you take it off it takes some time for the effects to wear off as it is slowly absorbed into the skin. Doubling the patch does seem extreme but I assume if you double the patch you wont use the MS Contin? I would get clarification from your doctor if you didnt understand whether to discontinue the MSContin.
I know we are programmed to think that these drugs are horrible for us, but they are required in this situation (and others) and certainly an addiction problem is the least of the worries. I think the bottom line is that pancreatic cancer is a very painful condition, and whatever can be done to eliminate suffering, should be done to allow the person to have some sort of comfort and dignity should be done. Adding extra pain medicine may put the person to sleep for most of the time. It may be disturbing for you to lose that time with them, but it seems kind to try to keep it under control if you can. I don't believe in blindly following medical advice but certainly an experienced oncologist has seen this condition and understands the risks of medicine vs. the benefits.
Your family will be in my thoughts and prayers.