Salvinorins

Neoclerodane diterpenes from Salvia divinorum, and unusual among potent receptor ligands in containing no nitrogen at all — so nothing about the structure predicts where they act. Salvinorin A is a selective agonist at the κ-opioid receptor. Salvinorin B is the deacetylated form and is not active there; herkinorin, a semi-synthetic derivative, moves the selectivity to μ instead. The family's defining receptor is therefore a property of individual members rather than of the scaffold.

They are not filed under Psychedelics because there is no 5-HT2A activity, and not under Opioids because κ agonism shares neither the experience nor the overdose picture of a μ agonist — naloxone is not the relevant tool here. What actually goes wrong is the onset: smoked salvinorin A takes effect faster than a person can put down what they are holding, and the injuries reported are falls, burns and walking into things.