Adverse effects
I once had a very bad experience with 5-MeO-MIPT and Methylone: I took 12mg of 5-MeO-MIPT (around my usual dose) with 300mg of Methylone (a high dose for me but I had some tolerance). Two hours post-ingestion I felt very stoned and kept zoning out. At this point I decided I didn't feel the normal effects of either substance (I felt quite relaxed from the Methylone, but I couldn't feel the 5-MeO-MIPT at all) so I re-dosed with 225mg of Methylone (remember, I had pretty high tolerance from a methylone dose/re-dose experience the day before) and another 12mg of 5-MeO-MIPT. 20 minutes later (!) I felt extremely stoned, almost as if I were nodding from opiates. A short time later the "zoning out" or dissociating sensation became too overwhelming. What had been a gentle zoning out or dissociation feeling gave way to the sense that I was going to lose consciousness. I told myself that I was in no real danger and I took 800mg of gabapentin (Neurontin) to try to calm the rising panic.
Over the next four hours (beginning at +3 hours first dose and +1 hour re-dose) I experienced tremendous pain in my sides, in my flanks to be exact (approximately near the location of my kidneys). At first I thought this was just severe muscle tension, but it quickly progressed to sharp piercing pains that felt far different from muscle pain. Then I began vomiting repeatedly. It would start as a slowly rising wave of nausea and general feeling of malaise and quickly progress to overwhelming sensations of heat, parethesia, and fainting sensations that, once I vomited, suddenly abated. Eventually I stopped vomiting stomach contents and dry heaved, incredibly painful dry heaves, but they made all of the other horrible sensations go away for a little bit. To combat the sensation of fainting I spent a lot of time walking around in circles in my apartment, for some reason I was convinced that this would keep me alive. It seemed that any time I stayed still, whether seated, laying down, or standing, the sensation that I was going to pass out became too overwhelming. My blood pressure seemed rather high and I certainly had tachycardia. I didn't know what was wrong with me but I entertained the horrible notion at various times that this was a potentially serious situation involving my heart and/or kidneys. For neither the first nor last time in my life, I thought I was going to die. Finally the symptoms slowly disappeared and I was thankful to be (mostly) normal again. Aside from sleeping for 12+ hours the following day, I experienced no other physical after-effects, though mentally I was a bit shaken for a few days.
I'm still not sure what happened. I'd combined both substances one time before and it found it weak (the Methylone overshadowed the Moxy entirely, hence the higher doses this time). Needless to say, I won't be repeating the combination, as 5-MeO-MIPT is weird enough (in good and bad ways) on its own.