IIRC, the action of agent BZ [quinuclidin-3-ol benzylate] sounds similar. But then, I might be wrong.
The Israelis have shown that jihadists like to toss together concoctions including everything they can find, so one cannot rule out that its a whole bunch of various toxic agents - perhaps arsenic (bloody vomiting), strychnine (for convulsions), and a whole lot of various junk. Or there could be a 'Love Canal' in the neighborhood. What I've seen of Russia, Ukraine, and Kazakhstan could qualify as a toxic waste dump ;-)