Potassium nitrate powder

Acute oral toxicity (LD50): 1901 mg/kg in rabbits MSDS and 3750 mg/kg in rats .
[L1736]


The primary acute toxic effect of nitrates is the development of methemoglobinemia, a condition in which greater than 10% of the hemoglobin in the body is transformed into methemoglobin. When this conversion exceeds 70% the condition may result in death .
[L1750]


The potassium ion by itself possesses very little toxicity; the toxicity of the salts is associated with the anion. Potassium nitrate is rapidly absorbed from the upper gastrointestinal tract and is excreted mostly as the unchanged drug .
[L1736]
This excludes a small percentage of the ingested dose that is reduced by the microbial action of the gut to nitrite.

Nitrites convert the hemoglobin in red blood cells into methemoglobin .
[L1736]
In male rats given potassium nitrate, intestinal absorption was affected .
[A32165]


Adverse increased potassium intake included changes in blood lipids, triglyceride, decreased high-density lipoprotein HDL cholesterol), changes in renal function, and increases in catecholamine levels. The decrease in blood volume caused by increased potassium activates the sympathetic nervous system, resulting in the release of adrenaline and noradrenaline. Decreases in blood volume may also contribute to the observed changes in blood lipid concentrations .
[L1755]


Death and severe effects of nitrate ingestion are generally associated with doses of the drugs above 10g NO3-.

Doses ranging from 2-9 g NO3- have been reported to cause methemoglobinemia. These values correspond to 33 - 150 mg NO3-/kg [L1750]
Potassium nitrate was shown to cause low to moderate acute toxicity. Repeated dose toxicity was investigated in rats given oral doses in the range 10-100 mg/kg per day for 4 months; bronchopneumonia, local hemorrhages, and other circulatory disorders were observed in treated animals. Cattle were given oral doses of 345-450 mg/kg daily (expressed as nitrate) for several months; blood phosphate and magnesium were decreased and blood calcium, urinary magnesium, urea and milk urea were increased .
[L1736]