There is a misconception that I heard from Octavio Rettig, a controversial toad venom enthusiast, that bufotenine transforms into 5-MeO-DMT in the body. It doesn't.
It's actually the inverse, when 5-MeO-DMT is consumed orally together with MAOI some bufotenine is produced through O-demethylation by the cytochrome P450 2D6 enzyme (
source). This could be one of the reasons why there have been issues reported with oral consumption of 5-MeO-DMT with MAOIs, even a couple of fatal cases (source
1,
2). Some people report no problems (for example
Ott's pharmepena article). Vaporized should not be the same concern since without the MAOI it will be deaminated to 5-MIAA and excreted instead of transformed to bufotenine.
Bufotenine also has been tested orally with unpleasant effects according to some anecdotes but some people also take without side effects (check
Pharmañopo by Ott )
Also, the Bufo alvarius venom contains mostly 5-MeO-DMT. I tested some from Octavio and it was only 5-MeO-DMT, no bufotenine detected. One paper (Erspamer et al. 1965) says 50-150 mg/g of 5-MeO-DMT in glands vs only 0.8-5 mg/g of bufotenine.
The toad venom will contain "fillers" too, or more accurately said, non-psychoactive natural substances that will just add weight to the whole thing, so a dosage of toad venom is probably weaker by weight than pure 5-MeO-DMT.