sigma receptor agonist (Ki = 205 nM and 11,060 nM, respectively).
The drugs and the enzymes they probe are as follows - caffeine (probes CYP1A2, N-acetyltransferase 2, xanthine oxidase), midazolam (probes CYP3A), omeprazole (probes CYP2C19) and dextromethorphan (probes CYP2D6).