Usage and mechanism of the Bastien protocol to treat amanitin poisoning
I know nothing about this subject, except that I can recognize edible and poisonous fungi, to the extent that it concerns me in a practical sense. However, as I have access to a range of journals through my university I thought I would see if there was anything ‘out there’ on the topic.

A recent paper entitled Amanita phalloides poisoning: Mechanisms of toxicity and treatment by J. Garcia et al. in Food and Chemical Toxicology 86 (2015) 41–55 contains a table listing the drug therapy used in a range of countries. There is no reference to Bastien in this paper and the most frequently used therapies are benzylpenicillin and silybin. 

Abiocine is another name for dihydrostreptomycin and nifuoxazide is nifuroxazide is an oral nitrofuran of questionable efficiacy. So they are not identical to the agents mentioned and Bastien’s protocol does not appear to be in current use.

The impression I get from the article is that the agents used for treatment are not strict antidotes, but rather part of a strategy to treat the general effects of the poison. To eliminate the poison activated charcoal is often used.

If Bastien’s protocol really had an effect I imagine it may have acted in a similar manner to the current agents, although I have no idea what the vitamins might have been doing (if anything). Incidentally it was the subject of a letter (in English) to Lancet in 1981, in response to previous scepticism expressed in a previous editorial.