I developed an allgeric reaction to these after 48 hrs. I am now allergic to everything in the morphine family. I hope these work for you
From a practical standpoint, it is splitting hairs to say that statement is probably wrong, since the bottom line is you must avoid them, but the details on how the hair can be split might be interesting.
1. Fentanyl is an opioid, not an opiate. Its chemical structure bears little resemblence to the drugs in the opium-derived families.
2. As a consequence of #1, it is quite a bit less likely to react with immune molecules that fit morphine.
3. Small molecules do not make good allergens. Sometimes, they can react with large molecules in the blood or tissue, altering them so that immune cells no longer recognize them as family and make immune molecules to attack. Neither fentanyl nor the opiates are very reactive in the chemical sense, hence they are not likely to do this.
4. If the reaction was itching, it has recently been shown that is an effect of the interaction of the opiate or oioid with the mu receptor on nerve cells. Th mu receptor is the principal point of action for these; if you block that, you block the pain-relieving effect. Benadryl is not very helpful in treating the itching, but narcotic antagonists are. This may at times be an important distinction. If you are allergic to a drug, taing it risks fatal anaphylactic reactions, and you may have to avoid it, no matter how high the need for it may become. If the reaction was itching, you could weigh that aainst the severity of the pain and decide to tolerate the itch.
I am a physician specializing in occupational and environmental medicine. I am not an authority on HMS or EDS, but find I have several patients with the condition and am trying to learn more.