I agree with you, Annie; when olga is described as "already old" and no more beautiful in Siberia, i thought it was not only because she was depressed, but also because she had arsenic in her veins.
I asked my brother in law (he studies to become a doctor and has quite finished) but he couldn't answer; he said that nowadays they don't use arsenic anymore, so he doesnt' know well how it worked on one's health.
No I believe they were just in 1916...certainly not in Siberia...
I have an extract of one of alix's letters to Nicky where she talks about arsenic injections. It's dated 31 october 1915, i know 'cause i used it in a novel, but i've only in italian. Try a rough translation:
Zarskoje Selo, 31 Ottobre 1915
(…) Ol'ga si è alzata solo per un giro in macchina e adesso, dopo il té, resta sul divano e noi ceneremo al piano di sopra. (…) Deve stare sdraiata più a lungo, perché se ne va in giro troppo pallida e stanca, e le iniezioni di arsenico faranno effetto più velocemente, così, capisci?(...) Today Olga got up just for a drive tour, but now, after tea, she lays on the sofa, and we'll have dinner upstairs. (...) she has to lay for a long time, 'cuase when she goes around she looks so pale and tired, and (if she lays down) the arsenic injections will have a faster effect, you know?