From the article: > biggest obstacle to the usefulness of opioids: euphoria Judging from the article, I'm going to guess AT 121 should be included in all the other synthesized opiates and should be avoided. Doctors will happily put people on anti depressants which fry their liver and kidneys while also increasing the suicide risk. God forbid the pain killer makes you feel good as well for no extra cost. Considering how toxic many classes of painkillers are, the notion that opiods making you feel good is a terrible side effect is laughable and should demonstrate how safe they really are. Also, "it is 100 times more potent than morphine for pain relief" seems like another red flag. You don't need particularly high doses of morphine to be effective (assuming it provides you relief). Extremely potent meds vastly increase the odds of overdose and complicate proper tapering for those who attempt to get off the medication.