Crimidine is a

convulsant A convulsant is a drug which induces convulsions and/or epileptic seizures, the opposite of an anticonvulsant. These drugs generally act as stimulants at low doses, but are not used for this purpose due to the risk of convulsions and consequent exc ...

poison used as a

rodenticide Rodenticides are chemicals made and sold for the purpose of killing rodents. While commonly referred to as "rat poison", rodenticides are also used to kill mice, squirrels, woodchucks, chipmunks, porcupines, nutria, beavers, and voles. Despi ...

. Crimidine was originally known by its product name, Castrix. It was originally produced in the 1940s by the conglomerate,

IG Farben Interessengemeinschaft Farbenindustrie AG (), commonly known as IG Farben (German for 'IG Dyestuffs'), was a German chemical and pharmaceutical conglomerate. Formed in 1925 from a merger of six chemical companies— BASF, Bayer, Hoechst, Agf ...

. It is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S.

Emergency Planning and Community Right-to-Know Act The Emergency Planning and Community Right-to-Know Act of 1986 is a United States federal law passed by the 99th United States Congress located at Title 42, Chapter 116 of the U.S. Code, concerned with emergency response preparedness. On October ...

(42 U.S.C. 11002), and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities. It is also no longer used in the United States as a rodenticide, but is still used to this day in other countries.

Mechanism of action

Crimidine is a highly reactive compound. The main mechanism of toxicity with crimidine is that it inhibits

vitamin B6 Vitamin B6 is one of the B vitamins, and thus an essential nutrient. The term refers to a group of six chemically similar compounds, i.e., " vitamers", which can be interconverted in biological systems. Its active form, pyridoxal 5′-phosp ...

, which is used in the metabolism of

carbohydrates In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or m ...

and

amino acids Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...

. This is due to the

pyrimidine Pyrimidine (; ) is an aromatic, heterocyclic, organic compound similar to pyridine (). One of the three diazines (six-membered heterocyclics with two nitrogen atoms in the ring), it has nitrogen atoms at positions 1 and 3 in the ring. The othe ...

ring that both compounds contain. Although, the exact mechanism of how crimidine antagonizes vitamin B6 is unknown. Another mechanism of toxicity with crimidine is due to its deactivating effect on

acetylcholinesterase Acetylcholinesterase ( HGNC symbol ACHE; EC 3.1.1.7; systematic name acetylcholine acetylhydrolase), also known as AChE, AChase or acetylhydrolase, is the primary cholinesterase in the body. It is an enzyme that catalyzes the breakdown of ac ...

The

serine Serine (symbol Ser or S) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α- amino group (which is in the protonated − form under biological conditions), a carboxyl group (which is in the deprotonated − for ...

residue, which is part of the acetylcholinesterase, acts a

nucleophile In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they ar ...

and eventually replaces the C-Cl bond that is present in crimidine. Unlike with acetylcholine, the resulting serine-crimidine bond does not hydrolyze, permanently deactivating the enzyme

Toxicity

Crimidine is a fast acting convulsant, with an LD50 of 5 mg/kg. Earliest symptoms can develop within 20–40 minutes. These symptoms can include burning, irritation, and itching at the site of exposure or intake. Following these initial symptoms, convulsions follow and can be fatal. Low dose, long-term exposure can lead to damage in the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all p ...

, resulting in muscle stiffness, restlessness, and sensitivity to light and noise. Although crimidine is fast acting, it is also quickly secreted and can pass through the system in less than 24 hours.. intravenous vitamin B6 should be given as soon as poisoning is suspected

References

External links

* {{Convulsants Convulsants Pesticides Pyrimidines Chloroarenes Acetylcholinesterase inhibitors Chloropyrimidines Vitamin B6 antagonists Neurotoxins Dimethylamino compounds