I know that it isn't an ADD question but I've difficulties to understand what a Ki value can tell exactly about a drug action and how to understand/interpret this. Can you explain it to me or post some links where I can find more information about this?
I agree, though I do find it somewhat ironic that a compound developed as a "non neurotoxic" MDMA ended up with this cardiotoxic property. I don't see the other values (eg the pEC50 of 6.1373 for mephedrone or 6.3936 for 1-naphyrone) as insignificant, for instance. It's not surprising that the compounds of this class are cardiotoxic to some degree, the strength of 6-APB / 5-APB at 5-HT2B is a bit surprising, but that's it.