I have to second the warning of going slow with MXE + weed. Earlier this week I passed out for about 10-15 seconds in a state resembling a seizure (as reported by a third party).
This occurred at least 6 hours after administering the last dose of MXE (100mg, after a previous initial dose of 130mg). Needless to say, prior to smoking I had felt pretty close to baseline, other than that residual fuzzy feeling you get during the day following a high dosage. Anyway, at this time 6 hours after the MXE, I smoked a couple of strong joints of hash which had me pretty baked. My whole body started buzzing and I stood up to go inside which caused a headrush. I've been smoking for years and am pretty experienced but knew I had to chill for a while until I was more capable. However, having gone inside and sat down again, this state which was intensified by the headrush only continued to slowly build over a period of a couple minutes. I was seeing stars which proceeded to cloud my vision more and more in a haze of white and also started to sweat profusely. During this time I was able to communicate most of this to a friend and also felt fully aware that I may pass out if it intensified much further. Anyway, I guess it did and I eventually left reality for a brief period in this haze of white in an experience resembling a strong hit of nitrous oxide - minus the euphoria.
After a period of about 10-15 seconds I returned to a very concerned friend. The intensity quickly subsided and I took steps to look after myself in the form of electrolytes and food. During this period I was allegedly slouched back in the chair, with a limp neck, my eyes open and rolled back in my head and not breathing.
I should add that I was pretty sleep deprived and in a fasted state (having been up most of the night due to the prior doses of MXE).
To my layman mind, I feel what may have happened was the beginning of a near-death experience not unlike those outlined by Karl Jansen in his book: Ketamine: Dreams and Realities:
...but of course I could be wrong. Any comments would be appreciated.