Thank you for your reply.
So my general impression is that red blood cells are failing to get adequate oxygen, even in cases where the lungs aren't, per se, filled up with fluid to interfere with oxygenation of the blood. I saw a comment somewhere, and I can't find it at the moment, comparing this to altitude sickness, which is a thing I have read up on and which makes some sense to me in terms of my impression of the pathology here.
So what specific pathway would inhibit uptake of oxygen, even in the absence of pneumonia? Typically, that's a side effect of anemia, which can be caused by either lack of B vitamins or lack of iron (which I understand to be also called Heme -- correct me if I'm wrong as I am a lay person here, not a medical professional).
So I'm trying to envision a specific chemical process that disrupts uptake of oxygen or binding of oxygen to the red blood cell and which is not anemia.
This sounds an awful lot like how carbon monoxide poisoning works. So maybe that's a mechanism to look at. The body can be fooled, either by viruses or chemicals of various sorts, to lock up those pathways with things that interfere with what we need.
This is, as I understand it, how Zithromax causes magnesium deficiency: The drug binds to the same receptors as magnesium, so they compete for uptake in the body. You cannot successfully take them together. Taking them together both makes the antibiotic less effective (it should be taken, in fact, with something acid, not something alkaline) and it also prevents the body from adequately absorbing the magnesium.
In practice, the way around this is to time your use of Zithromax and magnesium so that uptake occurs at different hours of the day and they don't compete. This is possible because of the relatively long half life of Zithromax, which means you don't need frequent dosing.
So this is the kind of mental model I'm trying to wrap my mind around. I know some of these types of antagonistic processes exist and if we can figure out what the mechanism is here for how people are basically suffocating, it should cast light on a solution.