Hi BrenBren. I understand your situation completely. Fentanyl is the most powerful pain medication available. Once you reach the maximum dose and still become tolerant, you must turn to your BT meds (because rotating to a different primary narcotic will result in far more pain). Believe me. I've been there. You could ask your doctor about wearing two patches. The worst that happen is he'll say, "No." But, research has established that people can live with very high dosages of narcotics without damage. The trick is to increase the dosage very gradually. Still, most physicians fear respiratory depression with more than one 100 mcg patch at a time. Some terminal cancer patients wear more than one 100 mcg patch at a time. I've heard of some people who wear one 100 mcg patch and another 15 mcg or 25 mcg patch simultaneously.
Some people (like me and maybe you) have an unusually-high tolerance for pain medications (CNS depressants). I've always required more than a normal amount of pain medication to achieve the expected result. The same applies to alcohol. When I was in college, I could drink everyone under the table and still appear sober. Some of us have a genetic predisposition to CNS-depressant tolerance. But, I don't know if saying that will convince your doctor to allow you to wear two patches.
I have had good results with Oxycodone for BT medication. But, even then, I periodically become tolerant. When that occurs, I rotate to Marinol for a couple of months. Marinol's active ingredient is THC (yes, the same ingredient in marijuana). Research reveals that THC binds with opioid receptors in the brain, just like opioids (narcotics). Frankly, Marinol does not relieve pain as well as Oxycodone, for me. But, it is an adequate substitute until my Oxycodone tolerance has been dissipated. Some people say that smoking it is far more efficacious than acquiring the drug via a capsule. Certainly, it enters the bloodstream mush faster via pulmonary ingestion. And, there are additional chemicals that enter the bloodstream via pulmonary ingestion. But, smoking can damage tissues, is potentially carcinogeous and the added chemicals can be dangerous to the heart. In the end, ingesting THC via the stomach results in a similar plasma level (although it takes longer to work), plus it seems to last longer.
Will your doctor allow you to rotate to Marinol? Maybe not. It is off label for pain (it was designed to treat the nausea and weight loss associated with chemotherapy). My doctor is exceedingly liberal about allowing me to do the research and try new ideas. Most doctors are not so generous.
In the end, you and I are at the same place. When you reach the strongest safe dosage of the strongest pain medications, there is nothing comparable for rotation. In essence, we must "grin and bear it." Perhaps in the not too distant future, something stronger than Fentanyl will arrive. You can also look at it from the other side. Many chronic pain patients suffer needlessly because their physicians are afraid to prescribe Fentanyl in the first place. To be honest, without Fentanyl, I would likely decide not to live. So, we're fortunate to have Fentanyl, even when we are tolerant to it. If you ever doubt the efficacy of Fentany, feel free to rotate to something different. I did. You do not want to know how that felt.
BrenBren, you likely know that hyperalgesia is exceedingly rare. Most physicians will practice a lifetime and never see it. If you had it, you would have noticed a significant increase in pain upon starting the medication, not long after that time. I would bet the mortgage (or what little is left of it) that you do NOT have hyperalgesia. You have severe chronic pain and tolerance, just like me.
Best of luck to you. And, know that I am out there researching every day. If I see something new, I'll post it here. Feel free to do the same.