Technically there are a handful in the US right now but the only (common) one that is relatively safe is o-desmethyltramadol. And even that can kill a person who isn't tolerant or if dosed to high (particularly in conjuction with benzos).
Technically there are a handful in the US right now but the only (common) one that is relatively safe is o-desmethyltramadol. And even that can kill a person who isn't tolerant or if dosed to high (particularly in conjuction with benzos).