Re: MDMA: Claudio Naranjo adminsitered harmaline in combination with MDA to volunteers (see Harmaline chapter). He briefly mentions this in
The Healing Journey, but unfortunately he says that he has chosen to only elaborate on his harmaline-only experiements (he also gave people harmaline and TMA).
And this is an Erowid trip report where someone consumed three MD
xs with ayahuasca and did not incur injury:
Jezebel. Fun, Plus 'Ghost People': An Experience with Ayahuasca, Mushrooms, MDMA, MDE, MDA, LSD, LSA, Blue Lotus, Cannabis, Alcohol, & Opium (ID 24742). Erowid.org. Jun 24, 2003.
erowid.org/exp/24742
One thing I know from looking at scientific literature is that the extent of MAO inhibition that an MAOI induces is measured on a percentage scale. Maybe the reason MD
x can be taken in combo with harmaline is that harmaline doesn't produce strong MAO inhibition in the brain.