Ultram is another that the seekers hate. It is narcotic-like, however has a weak affinity for the opioid receptor itself. So, they don't get the typical "euphoria" as with other opioid agonists. They go online and read this, and then suddenly have an "allergy" to it.
I once had this lady tell me that she was allergic to ibuprofen. So i asked her what she'd been taking for pain? She says, "Motrin." I couldn't help but laugh haha!
Most people don't realize that adding a simple anti-histamine will potentiate the effects of a narcotic significantly. This way you can give half the dose of the narcotic, and yield the same effects overall. It's a great way to cut down on huge doses of these narcotics. We utilize this all the time.