For those with anxiety, alprazolam's mainly anxiolytic effect (sedation isn't prominent at low doses, only a light muscle-relaxant, and no hypnotic properties) go well with MDMA. As long as the alprazolam dosage is lower in correlation to the user's tolerance and anxiety.
Too much alprazolam will make a roll nonexistent.
IMO opiate-naive dosages: anywhere from 0.25-1mg (no more than 1mg; i.e. 0.5 x 2 or 0.25 x 2, I'd save 1mg for the comedown)