Just a quick thought on this one, prompted by m0rl0ck's points.
Consider all the uncertainty that we see on these pages and elsewhere about the nature of jhana, concentration, mindfulness, clear comprehension, Samatha, and so on. As soon as anyone says they have attained one of these states, there are several, usually contradictory, opinions expressed as to why they are wrong. People cite the suttas, their teachers, and their own experiences in support of a multitude of views as to what these states are actually like. For example, a frequent assertion is that there is "wrong concentration", or "That's sati, but not Samma Sati!"
Adding an ingested chemical component takes one further away from what the Buddha was talking about. I would be so bothered that I was experiencing a chemically-induced "near miss", so to speak, that I would not trust what I had actually experienced. A bit like someone who is convinced they are really witty while drunk, or really insightful when stoned. Later they realise that they had not been. The concern that I would have an analogous experience would be enough to stop me taking any substance which apparently induced a wholesome mental state. It might do exactly that, or there again it might not. Why add another variable, along with all the current difficulties of translation, culture, and personal kamma?