I don’t normally post here but I felt compelled to answer.
If you cannot change her mind then I suggest you send her to www.erowid.org so she can research it and maybe make an informed decision. MDMA in it's pure form will not harm a healthy person. MDMA does not kill people, that is a common mistruth, however what you buy on the street WILL NOT be pure MDMA and will be cut with things like Methamphetamines, Procaine, Caffeine, Ketamine, Ephedrine, etc. & there is no way to tell what else is in it (unless she has a testing kit which I’m sure she does not) and those things can harm her, and I am sure can interact with her meds, that site provides some info about drug interactions (i.e. with MAOIs & SSRI's). Not worth the risk to me but there isn’t much you can do to stop her, she should at least be making an educated decision!