I am also interested in this topic. It sounds like it will mimic the behavior of "Euthasol". Maybe PN got the idea from that.
From
here,
"Several formulations of pentobarbital-containing veterinary euthanasia agents have varying types of Vaughan-Williams Class-Ib antiarrhythmics, most frequently phenytoin sodium. According to the Euthasol package insert, the rapid administration of these agents reportedly produces cardiotoxic effects during the anesthesia stage of euthanasia by "hastening the cessation of electrical activity of the heart" via interference with myocardial sodium channel function."
From
here,
- 1-2 grams of Phenytoin (Dilantin) will potentiate the cocktail according to Dr Nitschke and veterinary sources. However, veterinarians have raised warnings that phenytoin cardiotoxic effects may come into play prior to the barbiturates full anaesthetic effect, and may therefore cause unwanted pain.
I could not find much concrete data on Dilantin+N usage for humans. I asked one of the Dutch members for help in asking NVVE but she rebuffed me :)
Personally, I would be very reluctant to try it given the lack of data and the possibility of pain before passing out.