Just looking back at a few things ...
When sodium nitrite does its thing, it causes methemoglobinemia. If that goes as intended, tissues in the human body are starved from oxygen.
While the human brain is highly dependent on oxygen, there is no guarantee you lose consciousness before other unpleasant things happen.
I have a medscape login which I got a long time ago. These days, it may be harder to get full access. Medscape is intended for medical professionals.
https://emedicine.medscape.com/article/204178-overview
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Practice Essentials
Methemoglobinemia (congenital or acquired) occurs when red blood cells (RBCs) contain methemoglobin at levels higher than 1%. Methemoglobin results from the presence of iron in the ferric form instead of the usual ferrous form. This results in a decreased availability of oxygen to the tissues. Symptoms are proportional to the methemoglobin level and include skin color changes and blood color changes at levels up to 15% (see the image below). As levels rise above 15%, neurologic and cardiac symptoms arise as a consequence of hypoxia. Levels higher than 70% are usually fatal.'
'
Symptoms are proportional to the fraction of methemoglobin. A normal methemoglobin fraction is about 1% (range, 0-3%). Symptoms associated with higher levels of methemoglobin are as follows:
- 3-15% - Slight discoloration (eg, pale, gray, blue) of the skin
- 15-20% - Cyanosis, though patients may be relatively asymptomatic
- 25-50% - Headache, dyspnea, lightheadedness (even syncope), weakness, confusion, palpitations, chest pain
- 50-70% - Abnormal cardiac rhythms; altered mental status, delirium, seizures, coma; profound acidosis
- >70% - Usually, death'
While Nitschke has his 'opinions' (doctors!), he claims that cimetidine or ranitidine will increase absorption of the drug. We don't know how that works out in the real world. If you do not experience a very rapid rise in methemoglobinemia you would likely experience 'Headache, dyspnea, lightheadedness (even syncope), weakness, confusion, palpitations, chest pain' first. Then one could expect 'Abnormal cardiac rhythms; altered mental status, delirium, seizures, coma; profound acidosis '
https://en.m.wikipedia.org/wiki/Acidosis '
Nervous system involvement may be seen with acidosis and occurs more often with respiratory acidosis than with metabolic acidosis. Signs and symptoms that may be seen in acidosis include
headaches, confusion,
feeling tired,
tremors,
sleepiness,
flapping tremor, and dysfunction of the
cerebrum of the brain which may progress to coma if there is no intervention.
[2]'
And at very high levels, 'Usually, death' note that there hs been at least one reported case of someone who survived an extremely high level of methemoglobinemia.
There is no reason to believe these are the only possible symptoms. Starving the body of oxygen is the primary mechanism.
This is not the same as hypoxia as experienced by people in an airplane that is unable to supply the passengers and crew with sufficient oxygen. That is a more peaceful form.
My attempt to summarize a few things. I'm still waiting for Philip Nitschke to try it himself, which is not as dangerous at it seems since it is reversible with methylene blue.
I'd love to hear his firsthand experience. Beware fake reports mentioned on this website.