A quote from
@HannibalLector's post, different thread:
'
Sodium nitrite and lethal dose and reliability
"HUMAN EXPOSURE STUDIES/ Symptoms of nitrite poisoning and MetHb formation after ingestion ranged from 0.4 to > 200 mg/kg bw, expressed as nitrite ion ... MetHb formation in different cases varied from 7.7 up to 79% ... /It was deduced that/ cyanosis occurred at MetHb concentration above 10%, and other symptoms at > 20% ... /Nitrite" (toxic database)
A deeper look
"2.3.1 Methaemoglobin formation
Nitrite is more toxic to young infants than to adults, due to
the higher methaemoglobin formation in infants (section 2.1.2.2).
Accidental human intoxications have been reported due to the
presence of nitrite in food. The oral lethal dose for humans was
estimated to vary from 33 to 250 mg NO2-/kg bw, the lower doses
applying to children and elderly people (Corré & Breimer, 1979).
Toxic doses giving rise to induction of methaemoglobinaemia ranged
from 1 to 8.3 mg/kg bw (Winton
et al., 1971; Simon, 1970). Several
case reports of human intoxication from high nitrite exposure have
recently been published (Machabert
et al., 1994; Dudley & Salomon,
1993; Bradberry
et al., 1994; Kaplan
et al., 1990; Walley &
Flanagan, 1987). The toxicity of nitrite can be induced both from
inhalation (amyl nitrite) and oral intake (sodium nitrite, amyl
nitrite). The approximate intake figures were sometimes reconstructed
from residual nitrite in food products. Symptoms of nitrite poisoning
and MetHb formation after ingestion ranged from 0.4 to > 200 mg/kg
bw, expressed as nitrite ion. Symptoms of methaemoglobinaemia include
cyanosis, euphoria, flushed face, headache, dizziness, ataxia,
followed by dyspnoea and tachycardia, depending on the level of
exposure to nitrite. MetHb formation in different cases varied from
7.7 up to 79%. Patient recovered well due to therapy with methylene
blue combined with oxygen and/or ascorbic acid and in severe cases,
exchange transfusion (Kaplan
et al., 1990; Walley & Flanagan,
1987). From these case reports it was deduced that cyanosis occurred
at MetHb concentration above 10%, and other symptoms at > 20%. If no
therapy was immediately applied, concentrations of 60-70% MetHb
were often fatal (Kaplan
et al., 1990; Walley & Flanagan, 1987;
Bradberry
et al., 1994). Another source of information with
respect to nitrite toxicity in humans is the use of sodium nitrite
as medication for vasodilation or as antidote in cyanide poisoning.
Doses of 30-300 mg/person, equivalent to 0.5-5 mg/kg bw, did not
cause toxic effects (NAS, 1981)."
Other medical source about Methemoglobin Inducers
"The half-life of methemoglobin acutely formed as a result of exposure to oxidants is 1–3 hours. If there is continuous exposure to the oxidant, then the half-life of methemoglobin will appear prolonged. Certain compounds, such as dapsone, characteristically produce prolonged methemoglobinemia.
(toxicology literature, Methemoglobin Inducers)
If you are unfamiliar with the medical term "half-life":
"Half-life […] is the time required for a quantity to reduce to half its initial value."
https://en.wikipedia.org/wiki/Half-life
"
Cyanosis is a consistent physical finding and typically occurs when just 1.5
g/dL of methemoglobin is present, which represents approximately a 10%
methemoglobinemia. At 20–50% methemoglobin concentrations, dizziness,
fatigue, headache, and exertional dyspnea may develop. At approximately
50% methemoglobin, lethargy and stupor usually appear; and the lethal con-
centration is probably greater than 70%" (toxicology literature, Methemoglobin Inducers)
Conclusion
Reason for reported failures and scoring low on Nitschkes reliability test could be that humans more effective methemoglobin reductase. I also dicovered that dapsone produce prolonged methemoglobinemia. And that "continuous exposure" of sodium nitrite could possible increase likelihood of successful ctb. And it might be somewhat difficult achieve lethal levels methemoglobin (above 70%) when sodium nitrite ingestion from 0.4 to > 200 mg/kg only reaches methemoglobinemia levels of 7.7 up to 79%.
#21 HannibalLector,
Aug 16, 2018 '
Assuming this is correct, to keep it simple.
Specifically
'
"Cyanosis is a consistent physical finding and typically occurs when just 1.5
g/dL of methemoglobin is present, which represents approximately a 10%
methemoglobinemia. At 20–50% methemoglobin concentrations, dizziness,
fatigue, headache, and exertional dyspnea may develop. At approximately
50% methemoglobin, lethargy and stupor usually appear; and the lethal con-
centration is probably greater than 70%" (toxicology literature, Methemoglobin Inducers)'
To reach 70 % methemoglebemia it may take a lot. Let's keep in mind that the body tries to reverse the process.
And if the blood flow slows, so may the absorption and distribution of the SN.
If I'm not mistaken, you need to reach 100 % to block all the blood's ability to carry oxygen ?
A young and healthy body can usually withstand a lot. Then there is obviously genetic variation, the speed by which it is absorbed by the
intestines, and how effective that ranitidine/cimetidine really is. What if the stomach PH is off ?
95 % would probably kill, but would levels of 90 % kill quickly ?
There is very little reliable information. I know of at least one fake report on this website.
Knowledge is power.I'd like to know more. If
<bold> is correct, it could get quite unpleasant.
