C-8813 (thiobromadol) is a potent μ-opioid receptor agonist with a distinctive chemical structure which is not closely related to other established families of opioid drugs. The trans-isomer was found to be around 591 times more potent than morphine in animal studies. The same study assigned a potency of 504 times that of morphine to the related compound BDPC.
C-8813 is claimed to be similarly potent at the δ-opioid receptor, which antagonizes the mu depression of breathing, presumably making the drug safer.
C-8813 has never been used in humans.
Look out into the freeway eyes of the party. Look out into the dark spring sky at the party. You'd rather be anywhere than with this guy at the party. And now I'm taking it way too hard, I'm so fucking sorry. And now I know that I will become everything I hate eventually. And it puts me back in high school when I wanted to be cooler than I'd ever be. So I went walking from the party, Milwaukee Milwaukee. Walked out into the dark spring sky, left you hammered next to some other guys. Back in my bedroom red lights flashed. Its the first time that I ate food just because I was sad. And what do you care? What do you care? What do you care about?