N-Nitrosodimethylamine (NDMA)

N-Nitrosodimethylamine (NDMA), also known as dimethylnitrosamine (DMN).


It is an organic compound:(CH3)2NNO. 

A carcinogen N-nitrosdimethylamine recently found is a contamination and commonly used medications, ranitidine and valsartan.

NMDA and of nitrosamines are ubiquitous in outdoor air, water, and soil in minor amounts.

They are formed by a chemical interaction have a substituted amine  and oxidizing agent, usually an nitrate.

It is one of the simplest members of a large class of N-nitrosamines. 

In food, the nitrosating agent responsible for forming NDMA is usually nitrous anhydrite, which arises from a nitrate in acidic solution such as contained in the stomach.

Cured meats such as bacon or sausage,  water and tobacco contain nitrosamines in small amounts.

It is highly hepatotoxic and a known carcinogen in lab animals.

Nitrosamines in animal studies have found they are able to induce tumors in the liver, kidney, and respiratory tract.

It is a  known carcinogen.

It is a probable carcinogen in humans.

It can be produced by water treatment by chlorination or chloramination.

Nitrosamines are thought to act through metabolic activation and covalent interaction with DNA causing pro mutagenic abducts.

The FDA identifies 96 ng per day as the upper limit of safe daily ingestion for medications.

The allowable level is 10 nanograms/liter. 

The average intake of the volatile nitrosamines including NDMA  from food sources is about 1 µg per day.

Recycled water that can contain dimethylamine.


Further, NDMA can form or be leached during treatment of water by anion exchange resins.


NDMA’s contamination of drinking water, even at minute concentrations is harmful.


It is difficult  to detect NDMA at these concentrations, and it is difficult to remove it from drinking water. 


NDMA does not readily biodegrade, adsorb, or volatilize, and cannot be removed by activated carbon and travels easily through soils. 


Relatively high levels of UV radiation range breaks the N-N bond and can thus be used to degrade NDMA. 


Reverse osmosis removes approximately 50% of NDMA.


NDMA is found at low levels in numerous items including: cured meat, fish, beer, and tobacco smoke.


NDMA formation involves nitrous acid produced from sodium nitrite, which is used to cure meat.


NDMA arises possibly by the combination of nitrous acid and dimethylamine derived from the degradation of dietary protein in the lower gut.


The United States Environmental Protection Agency (EPA) has determined that the maximal admissible concentration of NDMA in drinking water is 7 ng/L, but has not set a regulatory maximal contaminant level.


At high doses, it is a  hepatotoxin, and animal studies suggest it can cause liver tumors.


It has been  found as an impurity in valsartan and other angiotensin II receptor blockers (ARBs) used to treat high blood pressure and heart failure, as has ranitidine, and metformin extended release.


Oral ranitidine compared with placebo does not increase 24 hour urinary excretion of NDMA when non-cured meats or cured meat diets are consumed.


Nitrosamines are classified as probable human carcinogens.


People should generally not be exposed to a lifetime risk of cancer exceeding 1 in 100,000 from nitrosamines in their medicines.


The mechanism of its carcinogenicity involves metabolic activation steps resulting in the formation of an alkylating agent.






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