I don't know if there are restrictions imposed on those who access this article from certain regions, but beyond a little prompt encouraging me to subscribe to the paper, I was able to access and read the article in its entirety without having to pay a £60 subscription fee. I haven't any idea where in the article it says Marjolein took SN pills, because one paragraph in particular stood out to me and I've included the original Dutch in the event that the machine translation failed somewhere:
Original Dutch: "De werking van Middel X is onomkeerbaar. Er is voor zover bekend geen tegengif. De stof legt de energie- en zuurstofvoorziening in de lichaamscellen vrijwel meteen stil. Wie voldoende binnenkrijgt, gaat bijna zeker dood."
English Translation via Google Translate: "The action of Agent [Middel] X is irreversible. There is no known antidote to it. The substance stops the energy and oxygen supply in the body cells almost immediately. Anyone who takes in enough will almost certainly die."
Marjolein is said to have taken a substance called "Middel X" to end her life and while the mechanism of action appears to be similar to that of SN, it was
not what was contained in those pills.
Middel X is instead thought to have been SA. For one, SN--ironically used in the clinical setting as an antidote for Cyanide poisoning--and the severe methemoglobinemia that follows ingestion can be treated with the antidote methylene blue. Second, the lethal dose of SA, as per
Philip Nitschke, is about 2g, a dose that is considerably more reasonable to be taken in pill form than the currently suggested 25g for SN. There are a few threads on the forum that deal with using pill capsules to take SN and dodge the unpleasant flavour but it was found that the size and number of pills required make that method of delivery rather cumbersome.