Cyanocobalamin
Systematic (IUPAC) name
α-(5,6-dimethylbenzimidazolyl)cobamidcyanide
Identifiers
CAS number	68-19-9
ATC code	B03BA01
PubChem	5479203
DrugBank	APRD00326
Chemical data
Formula	C63H88CoN14O14P
Mol. mass	1355.37 g/mol
Pharmacokinetic data
Bioavailability	readily absorbed in lower half ileum
Protein binding	Very high to specific transcobalamins plasma proteins Binding of hydroxocobalamin is slightly higher than cyanocobalamin.
Metabolism	hepatic
Half life	Approximately 6 days (400 days in the liver)
Excretion	renal
Therapeutic considerations
Pregnancy cat.	? Image File history File links VitaminB12. ... Image File history File links Download high-resolution version (1100x979, 292 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Cyanocobalamin Talk:Cyanocobalamin Ethics of eating meat ... IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... The Anatomical Therapeutic Chemical Classification System is used for the classification of drugs. ... A section of the Anatomical Therapeutic Chemical Classification System. ... PubChem is a database of chemical molecules. ... The DrugBank database available at the University of Alberta is a unique bioinformatics and cheminformatics resource that combines detailed drug (i. ... This article or section does not cite any references or sources. ... General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Standard atomic weight 12. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... wikipedia sucks big balls For other uses, see Cobalt (disambiguation). ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... General Name, Symbol, Number phosphorus, P, 15 Chemical series nonmetals Group, Period, Block 15, 3, p Appearance waxy white/ red/ black/ colorless Standard atomic weight 30. ... The molecular mass (abbreviated Mr) of a substance, formerly also called molecular weight and abbreviated as MW, is the mass of one molecule of that substance, relative to the unified atomic mass unit u (equal to 1/12 the mass of one atom of carbon-12). ... In pharmacology, bioavailability is used to describe the fraction of an administered dose of unchanged drug that reaches the systemic circulation, one of the principal pharmacokinetic properties of drugs. ... A drugs efficacy may be affected by the degree to which it binds to the proteins within blood plasma. ... Transcobalamins are carrier proteins which bind cyanocobalamin (B12). ... Hydroxocobalamin (OHCbl) is a natural analog of vitamin B12, a basic member of the cobalamin family of compounds. ... Drug metabolism is the metabolism of drugs, their biochemical modification or degradation, usually through specialized enzymatic systems. ... The liver is an organ in vertebrates including humans. ... It has been suggested that Effective half-life be merged into this article or section. ... Excretion is the process of eliminating waste products of metabolism and other materials that are of no use. ... Kidneys viewed from behind with spine removed The kidneys are bean-shaped excretory organs in vertebrates. ... The pregnancy category of a pharmaceutical agent is an assessment of the risk of fetal injury due to the pharmaceutical, if it is used as directed by the mother during pregnancy. ...
Legal status	POM(UK) The regulation of therapeutic goods, that is drugs and therapeutic devices, varies by jurisdiction. ... A prescription drug is a licensed medicine that is regulated by legislation to require a prescription before it can be obtained. ...
Routes	oral, iv

Cyanocobalamin is a compound that is metabolized to a vitamin in the B complex commonly known as vitamin B₁₂ (or B₁₂ for short). In pharmacology and toxicology, a route of administration is the path by which a drug, fluid, poison or other substance is brought into contact with the body 1. ... An intravenous drip in a hospital Intravenous therapy or IV therapy is the administration of liquid substances directly into a vein. ... Retinol (Vitamin A) For the record label, see Vitamin Records A vitamin is an organic compound required in tiny amounts for essential metabolic reactions in a living organism. ... The B vitamins are eight water-soluble vitamins that play important roles in cell metabolism. ...

Vitamin B12 is important for the normal functioning of the brain and nervous system and for the formation of blood. It is involved in the metabolism of every cell of the body, especially affecting the DNA synthesis and regulation but also fatty acid synthesis and energy production. Its effects are still incompletely known.

Terminology

The name vitamin B₁₂ is used in two different ways.

• In a broad sense it refers to a group of cobalt-containing compounds known as cobalamins - cyanocobalamin (an artifact formed as a result of the use of cyanide in the purification procedures), hydroxocobalamin and the two coenzyme forms of B₁₂, methylcobalamin (MeB₁₂) and 5-deoxyadenosylcobalamin (adenosylcobalamin - AdoB₁₂).

• In a more specific way, the term B₁₂ is used to refer to only one of these forms, cyanocobalamin, which is the principal B₁₂ form used for foods and in nutritional supplements. This use is being contested because research^{[citation needed]} indicates that it may not able to correct B12 deficiency in the brain effectively. Being an unnatural form of B12 it is misleading to equate it with the vitamin especially if it is not a fully effective supplement.

Pseudo-B₁₂ refers to B₁₂-like substances which are found in certain organisms, including spirulina and other algae; however, these substances do not have B₁₂ biological activity for humans. wikipedia sucks big balls For other uses, see Cobalt (disambiguation). ... The cyanide ion, CN−. From the top: 1. ... Hydroxocobalamin (OHCbl) is a natural analog of vitamin B12, a basic member of the cobalamin family of compounds. ... Cobamamide (also known as adenosylcobalamin) is a coenzyme form of cyanocobalamin. ...

Structure

B₁₂ is the most chemically complex of all the vitamins. The structure of B₁₂ is based on a corrin ring, which is similar to the porphyrin ring found in heme, chlorophyll, and cytochrome. The central metal ion is Co (cobalt). Four of the six coordination sites are provided by the corrin ring, and a fifth by a dimethylbenzimidazole group. The sixth coordination site, the center of reactivity, is variable, being a cyano group (-CN), a hydroxyl group (-OH), a methyl group (-CH₃) or a 5'-deoxyadenosyl group (here the C5' atom of the deoxyribose forms the covalent bond with Co), respectively, to yield the four B₁₂ forms mentioned above. The covalent C-Co bond is one of first examples of carbon-metal bonds in biology. The hydrogenases and, by necessity, enzymes associated with Cobalt utilization, involve metal-carbon bonds.^[1] A corrin is a polyaromatic ring related to the porphyrin ring in hemoglobin, consisting of 4 pyrrole subunits, joined on opposite sides by a C-CH3 methylene link, on one side by a C-H methylene link, and with the two of the pyrroles joined directly. ... Structure of porphine, the simplest porphyrin. ... Structure of Heme b A heme or haem is a prosthetic group that consists of an iron atom contained in the center of a large heterocyclic organic ring called a porphyrin. ... Chlorophyll gives leaves their green color Space-filling model of the chlorophyll molecule Chlorophyll is a green pigment found in most plants, algae, and cyanobacteria. ... Cytochromes are generally membrane-bound proteins that contain heme groups and carry out electron transport or catalyse reductive/oxidative reactions. ... wikipedia sucks big balls For other uses, see Cobalt (disambiguation). ... A cyanide is any chemical compound that contains the cyano group C≡N, with the carbon atom triple-bonded to the nitrogen atom. ... // Hydroxyl group The term hydroxyl group is used to describe the functional group -OH when it is a substituent in an organic compound. ... In chemistry a methyl-group is a hydrophobic Alkyl functional group which is derived from methane (CH4). ... Adenosine is a nucleoside comprised of adenine attached to a ribose (ribofuranose) moiety via a β-N9-glycosidic bond. ... A hydrogenase is an enzyme that catalyses the reversible oxidation of molecular hydrogen (H2). ...

Synthesis

B₁₂ cannot be made by plants or animals^[2], as the only type of organisms that have the enzymes required for the synthesis of B₁₂ are bacteria and archaea. The total synthesis of B₁₂ was reported by Robert Burns Woodward^{[3] [4]} and Albert Eschenmoser^[5][6], and remains one of the classic feats of total synthesis. Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... Phyla Crenarchaeota Euryarchaeota Korarchaeota Nanoarchaeota Archaea are a major division of microorganisms. ... A total synthesis is the complete chemical synthesis of complex organic molecules from simple, commercially available (petrochemical) precursors. ... Robert Burns Woodward (April 10, 1917–July 8, 1979) was an American organic chemist. ...

Species from the following genera are known to synthesize B₁₂: Aerobacter, Agrobacterium, Alcaligenes, Azotobacter, Bacillus, Clostridium, Corynebacterium, Flavobacterium, Micromonospora, Mycobacterium, Nocardia, Propionibacterium, Protaminobacter, Proteus, Pseudomonas, Rhizobium, Salmonella, Serratia, Streptomyces, Streptococcus and Xanthomonas. Industrial production of B₁₂ is through fermentation of selected microorganisms.^[7] The most used species are Pseudomonas denitrificans and Propionibacterium shermanii, often genetically engineered and grown under special conditions to enhance yield. For other uses of the word, please see Genus (disambiguation). ... Species Agrobacterium tumefaciens Agrobacterium rhizogenes áAgrobacterium is a genus of bacteria that causes tumors in plants. ... Species A. eutrophus A. faecalis etc. ... Species A. vinladii Azotobacter are usually motile, oval, or spherical bacteria, form thick-walled cysts, and may produce large quantities of capsular slime. ... Species Bacillus anthracis Bacillus cereus Bacillus coagulans Bacillus globigii Bacillus licheniformis Bacillus natto Bacillus subtilis Bacillus sphaericus Bacillus thuringiensis etc. ... Species Clostridium acetobutylicum Clostridium aerotolerans Clostridium botulinum Clostridium colicanis Clostridium difficile Clostridium formicaceticum Clostridium novyi Clostridium perfringens Clostridium sordelli Clostridium tetani Clostridium piliforme Clostridium tyrobutyricum etc. ... Species See text. ... Meningitis is inflammation of the meninges. ... Species see text Micromonospora is a genus of bacteria of the family Micromonosporaceae. ... Species See text. ... Nocardia is a genus of Gram-positive, catalase-positive, rod-shaped bacteria; some species are pathogenic (nocardiosis). ... Binomial name Propionibacterium acnes Propionibacterium acnes is a bacterium that is linked to the skin condition acne. ... This article is about Proteus in Greek mythology. ... Species group P. aeruginosa P. alcaligenes P. anguilliseptica P. argentinensis P. citronellolis P. flavescens P. mendocina P. nitroreducens P. oleovorans P. pseudoalcaligenes P. resinovorans P. straminea group P. aurantiaca P. aureofaciens P. chlororaphis P. fragi P. lundensis P. taetrolens group P. antarctica P. azotoformans P. cedrina P. corrugata P. fluorescens... Rhizobia (from the Greek words Riza = Root and Bios = Life) are soil bacteria that fix nitrogen (diazotrophy) after becoming established inside root nodules of legumes (Fabaceae). ... Species Salmonella bongori Salmonella enterica Salmonella arizonae Salmonella enteritidis Salmonella typhi Salmonella typhimurium Salmonella is a genus of rod-shaped Gram-negative enterobacteria that causes typhoid fever, paratyphoid fever, and foodborne illness. ... Serratia marcescens is a Gram negative bacterium, a human pathogen of the family Enterobacteriaceae. ... Streptomyces is a genus of Actinobacteria. ... Streptococcus is a genus of spherical shaped Gram-positive bacteria, belonging to the phylum Firmicutes[1] and the lactic acid bacteria group. ... Species X. albilineans X. ampelina X. arboricola X. axonopodis X. bromi X. campestris X. cassavae X. citri X. codiaei X. cucurbitae X. cynarae X. euvesicatoria X. frageriae X. gardneri X. hortorum X. hyacinthi X. melonis X. oryzae X. perforans X. phaseoli X. pisi X. populi X. sacchari X. theicola X... Fermentation in progress Fermentation typically refers to the conversion of sugar to alcohol using yeast. ... Binomial name Pseudomonas denitrificans Bergey, 1961 Pseudomonas denitrificans is an anaerobic bacteria that performs denitrification. ...

Functions

Coenzyme B₁₂'s reactive C-Co bond participates in two types of enzyme-catalyzed reactions. ^[8]

1. Rearrangements in which a hydrogen atom is directly transferred between two adjacent atoms with concomitant exchange of the second substituent, X, which may be a carbon atom with substituents, an oxygen atom of an alcohol, or an amine.
2. Methyl (-CH₃) group transfers between two molecules.

In humans there are only two coenzyme B₁₂-dependent enzymes:

1. MUT which uses the AdoB₁₂ form and reaction type 1 to catalyze a carbon skeleton rearrangement (the X group is -COSCoA). MUT's reaction converts MMl-CoA to Su-CoA, an important step in the extraction of energy from proteins and fats (for more see MUT's reaction mechanism). This functionality is lost in vitamin B₁₂ deficiency, and can be measured clinically as an increased methylmalonic acid level in vitro.
2. MTR, a methyl transfer enzyme, which uses the MeB₁₂ and reaction type 2 to catalyzes the conversion of the amino acid Hcy into Met (for more see MTR's reaction mechanism). This functionality is lost in vitamin B₁₂ deficiency, and can be measured clinically as an increased homocysteine level in vitro. Increased homocysteine can also be diagnostic of a folic acid deficiency. There is some controversy over whether it is the reduced availability of methionine, or the reduced availability of THF (produced in the conversion of homocysteine to methionine) that is responsible for the reduced availability of 5,10-methylene-THF. 5,10-methylene-THF is involved in the synthesis of thymine, and hence reduced availability of 5,10-methylene-THF results in problems with DNA synthesis, and ultimately in ineffective production of blood cells^[9].

These reactions have important secondary effects. The transformation of homocysteine to methionine is essential for the formation of transmethylating agent S-adenosylmethionine (SAMe). This substance is involved in the synthesis of myelin, which is essential for normal functioning of the nerves, which explains why B12 deficiency causes neuropathies. In addition, SAMe is involved in the manufacture of certain neurotransmitters, catecholamines and in the brain metabolism. These neurotransmitters are important for maintaining the mood, explaining why depression is associated with B12 deficiency. MUT is an enzyme that converts MMl-CoA into Succinyl-CoA (Su-CoA). ... Methylmalonyl-CoA is the coenzyme A linked form of methylmalonic acid. ... Categories: Biochemistry stubs ... MUT is an enzyme that converts MMl-CoA into Succinyl-CoA (Su-CoA). ... Methylmalonic acid is a malonate and dicarboxylic acid with an atomic weight of 118. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... Phenylalanine is one of the standard amino acids. ... Homocysteine is a chemical compound with the formula HSCH2CH2CH(NH2)CO2H. It is a homologue of the naturally-occurring amino acid cysteine, differing in that its side-chain contains an additional methylene (-CH2-) group before the thiol (-SH) group. ... Methionine (Met, M. C5H11NO2S) is an essential nonpolar amino acid, and a lipotropic. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... Homocysteine is a chemical compound with the formula HSCH2CH2CH(NH2)CO2H. It is a homologue of the naturally-occurring amino acid cysteine, differing in that its side-chain contains an additional methylene (-CH2-) group before the thiol (-SH) group. ... Homocysteine is a chemical compound with the formula HSCH2CH2CH(NH2)CO2H. It is a homologue of the naturally-occurring amino acid cysteine, differing in that its side-chain contains an additional methylene (-CH2-) group before the thiol (-SH) group. ... Folic acid and folate (the anion form) are forms of the water-soluble Vitamin B9. ... To meet Wikipedias quality standards, this articles references may require cleanup. ... For the similarly-spelled vitamin compound, see Thiamine Thymine, also known as 5-methyluracil, is a pyrimidine nucleobase. ... Myelin is an electrically insulating phospholipid layer that surrounds the axons of many neurons. ... Neuropathy strictly speaking is any disease that affects the neurons of the nervous system. ... Neurotransmitters are chemicals that are used to relay, amplify and modulate electrical signals between a presynaptic and a postsynaptic neuron. ... Catecholamines are chemical compounds derived from the amino acid tyrosine that act as hormones or neurotransmitters. ...

Human digestion

The human physiology of vitamin B₁₂ is complex, and therefore is prone to mishaps leading to vitamin B₁₂ deficiency. The vitamin enters the digestive tract bound to proteins, known as salivary R-binders. Stomach proteolysis of these proteins requires an acid pH, and also requires proper pancreatic release of proteolytic enzymes. The vitamin B₁₂ then attaches to gastric intrinsic factor, which is generated by the gastric parietal cells. The conjugated vitamin B₁₂-intrinsic factor complex can then be absorbed by the terminal ileum of the small bowel. Absorption of vitamin B₁₂ therefore requires an intact and functioning stomach, exocrine pancreas, intrinsic factor, and small bowel. Problems with any one of these organs makes a vitamin B₁₂ deficiency possible. The salivary glands in mammals are exocrine glands that produce saliva. ... In anatomy, the stomach is a bean-shaped hollow muscular organ of the gastrointestinal tract involved in the second phase of digestion, following mastication. ... Proteolysis is the directed degradation (digestion) of proteins by cellular enzymes called proteases or by intramolecular digestion. ... The correct title of this article is . ... The pancreas is a retroperitoneal organ that serves two functions: exocrine - it produces pancreatic juice containing digestive enzymes endocrine - it produces several important hormones Anatomy The pancreas is a retroperitoneal organ located posterior to the stomach on the posterior abdominal wall. ... Proteases (proteinases, peptidases, or proteolytic enzymes) are enzymes that break peptide bonds between amino acids of proteins. ... Intrinsic factor is a glycoprotein produced by the parietal cells of the stomach. ... In anatomy, the stomach (in ancient Greek στομάχι) is an organ in the alimentary canal used to digest food. ... Parietal cells (also called oxyntic cells) are cells located in the stomach epithelium. ... Intrinsic factor is a glycoprotein produced by the parietal cells of the stomach. ... Grays Fig. ... Diagram showing the small intestine In biology the small intestine is the part of the gastrointestinal tract between the stomach and the large intestine (colon). ... In anatomy, the stomach is a bean-shaped hollow muscular organ of the gastrointestinal tract involved in the second phase of digestion, following mastication. ... The exocrine pancreas has ducts which are arranged in clusters called acini (singular acinus). ... Intrinsic factor is a glycoprotein produced by the parietal cells of the stomach. ... Diagram showing the small intestine In biology the small intestine is the part of the gastrointestinal tract between the stomach and the large intestine (colon). ...

History as a treatment for anemia

B₁₂ deficiency is the cause of several forms of anemia. The treatment for this disease was first devised by William Murphy who devised experiments on anemia in dogs due to blood loss and then fed them various substances to see what (if anything) would make them healthy again. He discovered that ingesting large amounts of liver seemed to cure the disease. George Minot and George Whipple then set about to chemically isolate the curative substance and ultimately were able to isolate vitamin B₁₂ from the liver. For this, all three shared the 1934 Nobel Prize in Medicine. Anemia (AmE) or anæmia (BrE), from the Greek () meaning without blood, is a deficiency of red blood cells (RBCs) and/or hemoglobin. ... William Parry Murphy (Stoughton, Wisconsin, February 6, 1892 – October 9, 1987) was an American physician who shared the Nobel Prize in Physiology or Medicine in 1934 with George Richards Minot and George Hoyt Whipple for their combined work in devising and treating macrocytic anaemia. ... George Richards Minot (December 2, 1885 (Boston, Massachusetts, U.S.A.) - February 25, 1950) won the 1934 Nobel Prize in Physiology or Medicine with William P. Murphy and George H. Whipple for their work in the study of anemia. ... George Hoyt Whipple (August 28, 1878 – February 1, 1976) was an American physician, biomedical researcher, and medical school educator and administrator. ... Year 1934 (MCMXXXIV) was a common year starting on Monday (link will display full 1934 calendar) of the Gregorian calendar. ... List of Nobel Prize laureates in Physiology or Medicine from 1901 to the present day. ...

The chemical structure of the molecule was determined by Dorothy Crowfoot Hodgkin and her team in 1956, based on crystallographic data. Analytical chemistry is the analysis of material samples to gain an understanding of their chemical composition and structure. ... Dorothy Mary Crowfoot Hodgkin, OM , FRS (12 May 1910 – 29 July 1994) was a British founder of protein crystallography. ... Year 1956 (MCMLVI) was a leap year starting on Sunday (link will display full calendar) of the Gregorian calendar. ... Crystallography (from the Greek words crystallon = cold drop / frozen drop, with its meaning extending to all solids with some degree of transparency, and graphein = write) is the experimental science of determining the arrangement of atoms in solids. ...

Symptoms and damage from deficiency

B12 deficiency can potentially cause severe and irreversible damage, especially to the brain and nervous system.

The first deficiency symptom that was discovered was anemia characterized by enlarged blood corpuscles, so-called megaloblastic anemia. Megaloblastic anemia is an anemia (of macrocytic classification) which results from a deficiency of vitamin B12 and folic acid. ...

The anemia is thought to be due to problems in DNA synthesis, specifically in the synthesis of thymine, which is dependent on products of the MTR reaction. Other cell lines such as white blood cells and platelets are often also low. Bone marrow examination may show megaloblastic hemopoiesis. The anemia is easy to cure with vitamin B12. For the similarly-spelled vitamin compound, see Thiamine Thymine, also known as 5-methyluracil, is a pyrimidine nucleobase. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... A scanning electron microscope image of normal circulating human blood. ... A 250 ml bag of newly collected platelets. ... Grays Anatomy illustration of cells in bone marrow. ... Haematopoiesis is the formation of blood cellular components. ...

Far more serious is the damage to the nervous system that may occur due to deficiency.

Early and even fairly pronounced deficiency does not always cause distinct or specific symptoms. Common early symptoms are tiredness or a decreased mental work capacity, decreased concentration and decreased memory, irritability and depression.

Sleep disturbances may occur, because B12 may be involved in the regulation of the sleep wake cycle by the pineal gland (through melatonin)^[10].

Neurological signs of B₁₂ deficiency, which can occur without anemia, include sensory disturbances due to damage to peripheral nerves caused by demyelination and irreversible nerve cell death. Symptoms include numbness, tingling of the extremities, disturbed coordination and, if not treated in time, an ataxic gait, a syndrome known as subacute combined degeneration of spinal cord. In neuroscience, myelin is an electrically insulating fatty layer that surrounds the axons of many neurons, especially those in the peripheral nervous system. ... Paresthesia (paraesthesia in British) is a sensation of tingling, pricking, or numbness of the skin with no apparent physical cause, more generally known as the feeling of pins and needles. ... A stumbling, unsteady motion; also called motor ataxia. ... Subacute combined degeneration of spinal cord, also known as Lichtheims disease, refers to degeneration of the posterior and lateral columns of the spinal cord as a result of vitamin B12 deficiency. ...

Recent studies have devalued a possible connection between B12 deficiency and Alzheimer's dementia, and such a correlation is unlikely as of June 2007.^[11]

Studies showing a relationship between clinical depression levels and deficient B₁₂ blood levels in elderly people are documented in the clinical literature.^[12] and 2002 ^[13] Clinical depression (also called major depressive disorder, or unipolar depression when compared to bipolar disorder) is a state of intense sadness, melancholia or despair that has advanced to the point of being disruptive to an individuals social functioning and/or activities of daily living. ... For album titles with the same name, see 2002 (album). ...

Bipolar disease appears to genetically co-segregate with the hereditary B12-deficiency disorder pernicious anemia ^[14][15]. I think this is cool Pernicious anemia is loosely used to mean a state of anemia due to vitamin B12 deficiency. ...

Causes of deficiency

• Inadequate dietary intake of vitamin B₁₂, the most common cause of which is a vegan diet.^{[citation needed]} Vegans dispute this fact, and emphasize that vitamin B₁₂ is only manufactured by prokaryotic microorganisms, not in food livestock.^{[citation needed]}

• Selective impaired absorption of vitamin B₁₂ due to intrinsic factor deficiency. This may depend on loss of gastric parietal cells in chronic atrophic gastritis (in which case, the resulting megaloblastic anaemia takes the name of "pernicious anaemia"), or on wide surgical resection of stomach (such as in bariatric surgery), or on rare hereditary causes of impaired synthesis of intrinsic factor.

• Impaired absorption of vitamin B₁₂ in the setting of a more generalised malabsorption or maldigestion syndrome. This includes any form of structural damage or wide surgical resection of the terminal ileum (the principal site of vitamin B₁₂ absorption), forms of achlorhydria (including that artificially induced by drugs such as proton pump inhibitors), as well as bacterial overgrowth (such as in blind loop syndrome.

• Chronic intestinal infestation by the fish tapeworm Diphyllobothrium, that competes for vitamin B₁₂, seizing it for its own use and therefore leaving insufficient amount for the host organism. This is mostly confined to Scandinavia and parts of Eastern Europe (for example, in preparers of gefilte fish, who would acquire the tapeworm by sneaking bits of uncooked fish while making the Eastern European delicacy, now eaten by Jews at Pesach).

• The diabetes medication, metformin may interfere with B12 dietary absorption.^[16].

• Hereditary causes such as severe MTHFR deficiency, homocystinuria, and transcobalamin deficiency.

Hens kept in cramped conditions — the avoidance of animal suffering is the primary motivation of people who become vegans A vegan is a person who avoids the ingestion or use of animal products. ... Retinol (Vitamin A) For the record label, see Vitamin Records A vitamin is an organic compound required in tiny amounts for essential metabolic reactions in a living organism. ... Prokaryotes are unicellular (in rare cases, multicellular) organisms without a nucleus. ... A microorganism or microbe is an organism that is so small that it is microscopic (invisible to the naked eye). ... Sheep are commonly bred as livestock. ... Intrinsic factor is a glycoprotein produced by the parietal cells of the stomach. ... In anatomy, the stomach is a bean-shaped hollow muscular organ of the gastrointestinal tract involved in the second phase of digestion, following mastication. ... Parietal cells (also called oxyntic cells) are cells located in the stomach epithelium. ... Atrophic gastritis is a process of chronic inflammation of the stomach mucosa, leading to loss of gastric glandular cells and their eventual replacement by intestinal and fibrous tissues. ... Megaloblastic anemia is anemia resulting from a deficiency of vitamin B12 and folic acid. ... Pernicious anemia refers to a type of autoimmune anemia. ... Bariatrics is the specialty of medicine dealing with the surgical treatment of obesity. ... Malabsorption is the state of impaired absorption of nutrients in the small intestine. ... Grays Fig. ... Achlorhydria or hypochlorhydria is decreased production of gastric acid by the stomach. ... Proton pump inhibitors are a group of drugs whose main action is pronounced and long-lasting reduction of gastric acid production. ... Bacterial overgrowth is when theres too much bacteria in a certain place. ... Blind loop syndrome is a medical condition that occures when the intestine is obstructed, slowing or stopping the progress of digested food, and thus facilitating the growth of bacteria to the point that problems in nutrient absorption occur. ... Species Diphyllobothriasis is caused by the infestation of tapeworms, of the genus Diphyllobothrium. ... Species Diphyllobothriasis is caused by the infestation of tapeworms, of the genus Diphyllobothrium. ... Scandinavia is a historical and geographical region centered on the Scandinavian Peninsula in Northern Europe and includes the three kingdoms of Denmark, Norway and Sweden. ... Pre-1989 division between the West (grey) and Eastern Bloc (orange) superimposed on current national boundaries: Russia (dark orange), other countries of the former USSR (medium orange),members of the Warsaw pact (light orange), and other former Communist regimes not aligned with Moscow (lightest orange). ... Gefilte fish, (Yiddish: געפילטע פיש) is a ground de-boned fish recipe using a variety of kosher fish meat that is then made into fish loaves or balls, popular with many people of Ashkenazi Jewish heritage. ... Passover, also known as Pesach or Pesah (פסח pesaḥ), is a Jewish holiday (lasting seven days in Israel and among some liberal Diaspora Jews, and eight days among other Diaspora Jews) that commemorates the exodus and freedom of the Israelites from Egypt; it is also observed by... This article is about the disease that features high blood sugar. ... Metformin (INN; trade names Glucophage, Diabex, Diaformin, Fortamet, Riomet, Glumetza and others) is an anti-diabetic drug from the biguanide class of oral hypoglycemic agents. ... MTHFR, or Methylene-tetra-hydrofolate reductase is an enzyme that exists in human cells that assists with metabolism and the reduction of blood homocysteine levels. ... Homocystinuria, also known as Cystathionine beta synthase deficiency, is inherited disorder of the metabolism of the amino acid methionine. ... Transcobalamins are carrier proteins which bind cyanocobalamin (B12). ...

B12 deficiency is very common

Recent research indicates that B12 deficiency is far more widespread than formerly believed. A large study in the US found that 39 percent had low values.^[17] This study at Tufts University used the B12 concentration 258 pmol/l (= 350 pg/liter) as a criterion of "low level". However, recent research has found that B12 deficiency may occur at a much higher B12 concentration (500-600 pg/l). On this basis Mitsuyama and Kogoh ^[18]. proposed 550 pg/l, and Tiggelen et al ^[19] proposed 600 pg/l. Against this background, there are reasons to believe that B12 deficiency is present in a far greater proportion of the population than 39% as reported by the Tufts University.

B12 deficiency is even more common in the elderly ^[20]. This is because B₁₂ absorption decreases greatly in the presence of atrophic gastritis, which is common in elderly.

B12 deficiency is common among vegetarians. In vegans the risk is very high because virtually none of their natural food sources contain B12. One American study found blood levels below normal in 92 % of vegans, 64 % of lactovegetarians, 47 % of lacto-ovovegetarians ^[21]. The study applied the old normal values, so in reality a considerably greater proportion may have been deficient.

Diagnosis of B₁₂ deficiency

Serum B₁₂ levels are often low in B₁₂ deficiency, but if other features of B₁₂ deficiency are present with normal B₁₂ then the diagnosis must not be discounted. One possible explanation for normal B₁₂ levels in B₁₂ deficiency is antibody interference in people with high titres of intrinsic factor antibody.^[22] Some researchers propose that the current standard norms of vitamin B12 levels are too low^{[citation needed]}. In Japan, the lowest acceptable level for vitamin B12 in blood has been raised from about 200 picograms/litre (pg/l) = 145 picomol/litre (pm/l) to 550 pg/l = 400 pm/l^{[citation needed]}. ^[23]

Serum Homocysteine and Methylmalonic acid levels are considered more reliable indicators of B12 deficiency than the concentration of B12 in blood, see for example research at the St Louis University "Test used to diagnose B12 deficiency may be inadequate" . The levels of these substances are high in B₁₂ deficiency and can be helpful if the diagnosis is unclear. Approximately 10% of patients with vitamin B12 levels between 200-400pg/l will have a vitamin B12 deficiency on the basis of elevated levels of homocysteine and methylmalonic acid.^{[citation needed]} Homocysteine is a chemical compound with the formula HSCH2CH2CH(NH2)CO2H. It is a homologue of the naturally-occurring amino acid cysteine, differing in that its side-chain contains an additional methylene (-CH2-) group before the thiol (-SH) group. ... Methylmalonic acid is a malonate and dicarboxylic acid with an atomic weight of 118. ...

Routine monitoring of methylmalonic acid levels in urine is an option for people who may not be getting enough dietary B₁₂, as a rise in methylmalonic acid levels may be an early indication of deficiency.^[24] Methylmalonic acid is a malonate and dicarboxylic acid with an atomic weight of 118. ... Methylmalonic acid is a malonate and dicarboxylic acid with an atomic weight of 118. ...

If nervous system damage is suspected, B12 analysis in cerebrospinal fluid can also be helpful, though such an invasive test would be applicable only after unrevealing blood testing.^[25]

Treatment of B₁₂ deficiency

B₁₂ can be supplemented in healthy subjects by oral pill; sublingual pill, liquid, or strip; or by injection. B₁₂ is available singly or in combination with other supplements. B₁₂ supplements are available in forms including cyanocobalamin, hydroxocobalamin, methylcobalamin, and adenosylcobalamin (sometimes called "cobamamide" or "dibencozide"). Sublingual, literally under the tongue, from Latin, refers to a pharmacological route of administration in which certain drugs are entered directly into the bloodstream via absorption under the tongue. ... Hydroxocobalamin (OHCbl) is a natural analog of vitamin B12, a basic member of the cobalamin family of compounds. ... Chemical structure of Vitamin B12 The term vitamin B12 (or B12 for short) is used in two different ways. ... Cobamamide (also known as adenosylcobalamin) is a coenzyme form of cyanocobalamin. ...

Vitamin B₁₂ can be given as intramuscular injections of hydroxycobalamin, methylcobalamin, or cyanocobalamin. Body stores (in the liver) are refilled with half a dozen injections in the first couple of weeks and then maintenance with monthly to quarterly injections throughout the life of the patient. Hydroxocobalamin (OHCbl) is a natural analog of vitamin B12, a basic member of the cobalamin family of compounds. ... Chemical structure of Vitamin B12 The term vitamin B12 (or B12 for short) is used in two different ways. ... A patient having his blood pressure taken by a doctor. ...

B₁₂ has traditionally been given parenterally to ensure absorption. However, oral replacement is now an accepted route, as it has become increasingly appreciated that sufficient quantities of B₁₂ are absorbed when large doses are given. This absorption does not rely on the presence of intrinsic factor or an intact ileum. Generally 1 to 2 mg daily is required as a large dose [1]. By contrast, the typical Western diet contains 5–7 µg of B₁₂ (Food and Drug Administration (FDA) Daily Value ^[26]). Parenterally: administered into the body in a manner other than through the digestive tract, as by intravenous or intramuscular injection. ... FDA logo The Food and Drug Administration (FDA) is an agency of the United States Department of Health and Human Services and is responsible for regulating food, dietary supplements, drugs, biological medical products, blood products, medical devices, radiation-emitting devices, veterinary products, and cosmetics in the United States. ...

Hypokalemia, an excessive low potassium level in the blood, is anecdotally reported as a complication of vitamin B₁₂ repletion after deficiency. Excessive quantities of potassium are used by newly growing and dividing hematopoeitic cells, depleting circulating stores of the mineral. Hypokalemia is a potentially fatal condition in which the body fails to retain sufficient potassium to maintain health. ... General Name, Symbol, Number potassium, K, 19 Chemical series alkali metals Group, Period, Block 1, 4, s Appearance silvery white Standard atomic weight 39. ... Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte. ... General Name, Symbol, Number potassium, K, 19 Chemical series alkali metals Group, Period, Block 1, 4, s Appearance silvery white Standard atomic weight 39. ... A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition, a highly ordered atomic structure and specific physical properties. ...

It has been appreciated since the 1960s that deficiency can sometimes be treated with oral B₁₂ supplements when given in sufficient doses. When given in oral doses ranging from 0.1–2 mg daily, B₁₂ can be absorbed in a pathway that does not require an intact ileum or intrinsic factor. However, with the advent of sublingual and intranasal adminstration, tablet usage is becoming outdated. ^[27][28] Oral absorption is limited so regular intramuscular injections or sublingual/intranasal administration of a cobalamin (preferably methyl- or hydroxycobalamin) is necessary to restore systemic stores to physiological levels. Recent research indicates that sublingual administration eliminates a deficiency as well as injections (reference will be added) with the advantage of evading the allergy risk.

Sources

Vitamin B₁₂ is naturally found in foods that harbor B₁₂ bacteria including meat, especially liver and shellfish, and milk products. Eggs are usually mentioned as a good source, but this is not correct because eggs contain also a factor that blocks absorption (^[29] ) Fortified breakfast cereals are a particularly valuable source of vitamin B₁₂ for vegetarians and vegans. Table 1 lists a variety of food sources of vitamin B₁₂. A glass of cows milk. ... An egg is a body consisting of an ovum surrounded by layers of membranes and an outer casing of some type, which acts to nourish and protect a developing embryo. ... This article does not cite any references or sources. ... A variety of vegetarian food ingredients Vegetarianism is the practice of not consuming the flesh of any animal (including sea animals) with or without also eschewing other animal derivatives, such as dairy products or eggs[1]. Some vegetarians choose also to refrain from wearing clothing that has involved the death... The logo of the worlds first Vegan Society, registered in 1944. ...

Cyanocobalamin is converted to its active forms, first hydroxocobalamin and then methylcobalamin and adenosylcobalamin in the liver. A 2003 study found no significant difference in absorption for serum levels from oral vs sublingual delivery of 500 micrograms of cobalamin ^[30]. Injection is useful and usually necessary in cases where digestive absorption is impaired. Oral absorption is complex and requires specific intestinal transport proteins (intrinsic factor) produced in the stomach. In any case the absorption is saturated and is rate limited.

While lacto-ovo vegetarians usually get enough B₁₂ through dairy products, it may be found lacking in those practicing vegan diets who do not use multivitamin supplements or eat B₁₂ fortified foods, such as fortified breakfast cereals, fortified soy-based products, and fortified energy bars. Claimed sources of B₁₂ that have been shown through direct studies^[31] of vegans to be inadequate or unreliable include, nori (a seaweed), barley grass, and human gut bacteria. People on a vegan raw food diet are also susceptible to B₁₂ deficiency if no supplementation is used^[24]. The more alkaline intestines of vegans^{[citation needed]} are able to metabolize hydroxyl cobalamin preferentially, a more efficient cobalamin than cyanocobalamin.^{[citation needed]} A lacto-ovo vegetarian (or ovo-lacto vegetarian, also called eggitarian and sometimes incorrectly referred to as octo-lacto vegetarian, as octo means eight) is a vegetarian who consumes dairy products (i. ... Dairy products are generally defined as foodstuffs produced from milk. ... The logo of the worlds first Vegan Society, registered in 1944. ... A multivitamin is any preparation containing more than a single vitamin. ... Binomial name (L.) Merr. ... An energy bar is a dietary supplement often consumed by athletes or other physically active people to maintain their caloric needs in light of their strenuous physical activity. ... Nori. ... Ascophyllum nodosum exposed to the sun in Nova Scotia, Canada Dead Mans Fingers (Codium fragile) off Massachusetts coast For the Marine Biology Summer internship Marine Algae by Friday Harbor Laboratories, see; Marine Algae For the band, see; Seaweed (band) For the rock musician, see; Seaweed (musician) Seaweeds are any... Binomial name L. Barley (Hordeum vulgare) is an annual cereal grain, which serves as a major animal feed crop, with smaller amounts used for malting and in health food. ... A raw food diet consists of uncooked and unprocessed, and often organic foods. ... This article is about the dietary lifestyle, Vegan can also mean relating to vega, especially the star Vega, as in astronomical references to the Vegan system, or Science Fiction references to aliens from that system. ...

A natural vegan source of B₁₂ is the Chinese herb Dang Gui (Angelica sinensis) ^[32]. The herb is used in Traditional Chinese medicine for treating anemia.[2] Other potential sources of B₁₂ for vegans include Indonesian tempeh [3], ontjom, and other fermented food products. Spirulina, an algae that has recently gained popularity as a dietary supplement, may also contain some B₁₂. Another source of B₁₂ is yeast spreads, such as Marmite, which are suitable for vegetarians and vegans. Binomial name Angelica sinensis (Oliv. ... Traditional Chinese medicine shop in Tsim Sha Tsui, Hong Kong. ... A piece of uncooked tempeh. ... The current version of the article or section reads like an advertisement. ... A jar of the British version of Marmite Marmite is a British savoury spread made from yeast extract, a by-product of beer brewing. ...

The Vegan Society and Vegan Outreach, among others, recommend that vegans either consistently eat foods fortified with B₁₂ or take a daily or weekly B12 supplement.^[33][34] The Vegan Society is a registered charity in the United Kingdom, promoting the vegan diet. ... Vegan Outreach is a successful animal rights group working to promote an vegan lifestyle through methods generally considered less aggressive than those of fellow activist group, PETA. They distribute pamphlets, generally on college campuses, designed to educate the public on the realities of meat production, vivisection, and other related topics. ...

Interestingly, certain insects such as termites have been found to contain B₁₂. ^[35]

Cyanocobalamin may also found in many energy drinks, with over 80 times the recommended intake in some cases. A variety of energy drinks are available; the skinny bullet can shape is popular. ...

Allergies

Vitamin B₁₂ supplements should be avoided in people sensitive or allergic to cobalamin, cobalt or any other product ingredients. ‹ The template below (Taginfo) is being considered for deletion. ...

Side effects, contraindications, and warnings

• Dermatologic: Itching, rash, transitory exanthema, and urticaria have been reported. Vitamin B₁₂ (20 micrograms/day) and pyridoxine (80mg/day) has been associated with cases of rosacea fulminans, characterized by intense erythema with nodules, papules, and pustules. Symptoms may persist for up to 4 months after the supplement is stopped, and may require treatment with systemic corticosteroids and topical therapy.

• Gastrointestinal: Diarrhea has been reported.
• Hematologic: Peripheral vascular thrombosis has been reported. Treatment of vitamin B₁₂ deficiency can unmask polycythemia vera, which is characterized by an increase in blood volume and the number of red blood cells. The correction of megaloblastic anemia with vitamin B₁₂ can result in fatal hypokalemia and gout in susceptible individuals, and it can obscure folate deficiency in megaloblastic anemia. Caution is warranted.

• Leber's disease: Vitamin B₁₂ in the form of cyanocobalamin is contraindicated in early Leber's disease, which is hereditary optic nerve atrophy. Vitamin B₁₂ can cause severe and swift optic atrophy.

An itch (Latin: pruritus) is a sensation felt on an area of skin that makes a person or animal want to scratch it. ... A rash is a change in skin which affects its color, appearance or texture. ... An exanthem is a widespread rash, usually viral, and usually occurring in children. ... Main article: vitamin B6 Pyridoxine is one of the compounds that can be called vitamin B6, along with Pyridoxal and Pyridoxamine. ... Rosacea (IPA: ) is a common but often misunderstood condition that is estimated to affect over 45 million people worldwide. ... Erythema is an abnormal redness of the skin caused by capillary congestion. ... A nodule describes an aggregation of similar cells or particles in a number of scientific fields: In medicine it refers to a small aggregation of cells. ... A papule is a small, solid and usually conical elevation of the skin. ... An abscess is a collection of pus collected in a cavity formed by the tissue on the basis of an infectious process (usually caused by bacteria or parasites) or other foreign materials (e. ... In physiology, corticosteroids are a class of steroid hormones that are produced in the adrenal cortex. ... Types 5-7 on the Bristol Stool Chart are often associated with diarrhea Diarrhea (in American English) or diarrhoea (in British English) is a condition in which the sufferer has frequent watery, loose bowel movements (from the Greek word διάρροια; literally meaning through-flowing). Acute infectious diarrhea is a common cause... Thrombosis is the formation of a clot or thrombus inside a blood vessel, obstructing the flow of blood through the circulatory system. ... Polycythemia is a condition in which there is a net increase in the total circulating erythrocyte (red blood cell) mass of the body. ... Megaloblastic anemia is an anemia (of macrocytic classification) which results from a deficiency of vitamin B12 and folic acid. ... Hypokalemia is a potentially fatal condition in which the body fails to retain sufficient potassium to maintain health. ... Leber’s hereditary optic neuropathy (LHON) or Leber optic atrophy is a mitochondrially inherited (mother to all offspring) degeneration of retinal ganglion cells (RGCs) and their axons that leads to an acute or subacute loss of central vision; this affects predominantly young adult males. ... This article is about the anatomical structure. ... Atrophy is the partial or complete wasting away of a part of the body. ...

Pregnancy and breastfeeding

Vitamin B₁₂ is likely safe when used orally in amounts that do not exceed the recommended dietary allowance (RDA). The RDA for vitamin B₁₂ in pregnant women is 2.6mcg per day and 2.8mcg during lactation periods. This article needs additional references or sources for verification. ... Kittens nursing Lactation describes the secretion of milk from the mammary glands, the process of providing that milk to the young, and the period of time that a mother lactates to feed her young. ...

There is insufficient reliable information available about the safety of consuming greater amounts of Vitamin B₁₂ during pregnancy.

Other medical uses

Hydroxycobalamin, also known as Vitamin B12a, is used in Europe both for vitamin B₁₂ deficiency and as a treatment for cyanide poisoning, sometimes with a large amount (5-10 g) given intravenously, and sometimes in combination with sodium thiosulfate^[36]. The mechanism of action is straightforward, the hydroxycobalamin hydroxide ligand is displaced by the toxic cyanide ion, and the resulting harmless B₁₂ complex is excreted in urine. In the United States, the FDA has approved in 2006 the use of hydroxocobalamin for acute treatment of cyanide poisoning. Hydroxocobalamin (OHCbl) is a natural analog of vitamin B12, a basic member of the cobalamin family of compounds. ... The cyanide ion, CN−. From the top: 1. ... An intravenous drip in a hospital Intravenous therapy or IV therapy is the administration of liquid substances directly into a vein. ... Sodium thiosulfate (Na2S2O3) is a colorless crystalline compound that is more familiar as the pentahydrate, Na2S2O3•5H2O, an efflorescent, monoclinic crystalline substance also called sodium hyposulfite or “hypo. ... In chemistry, a ligand is an atom, ion, or molecule (see also: functional group) that generally donates one or more of its electrons through a coordinate covalent bond to, or shares its electrons through a covalent bond with, one or more central atoms or ions (these ligands act as a... This article or section is in need of attention from an expert on the subject. ... The United States Food and Drug Administration is the government agency responsible for regulating food, dietary supplements, drugs, cosmetics, medical devices, biologics and blood products in the United States. ...

Interactions

Interactions with drugs

• Alcohol (ethanol): Excessive alcohol intake lasting longer than two weeks can decrease vitamin B₁₂ absorption from the gastrointestinal tract.

• Aminosalicylic acid (para-aminosalicylic acid, PAS, Paser): Aminosalicylic acid can reduce oral vitamin B₁₂ absorption, possibly by as much as 55%, as part of a general malabsorption syndrome. Megaloblastic changes, and occasional cases of symptomatic anemia have occurred, usually after doses of 8 to 12 grams/day for several months. Vitamin B₁₂ levels should be monitored in people taking aminosalicylic acid for more than one month.

• Antibiotics: An increased bacterial load can bind significant amounts of vitamin B₁₂ in the gut, preventing its absorption. In people with bacterial overgrowth of the small bowel, antibiotics such as metronidazole (Flagyl®) can actually improve vitamin B₁₂ status. The effects of most antibiotics on gastrointestinal bacteria are unlikely to have clinically significant effects on vitamin B₁₂ levels.

• Birth control pills: The data regarding the effects of oral contraceptives on vitamin B₁₂ serum levels are conflicting. Some studies have found reduced serum levels in oral contraceptive users, but others have found no effect despite use of oral contraceptives for up to 6 months. When oral contraceptive use is stopped, normalization of vitamin B₁₂ levels usually occurs. Lower vitamin B₁₂ serum levels seen with oral contraceptives probably are not clinically significant.

• Chloramphenicol (Chloromycetin®): Limited case reports suggest that chloramphenicol can delay or interrupt the reticulocyte response to supplemental vitamin B₁₂ in some patients. Blood counts should be monitored closely if this combination cannot be avoided.
• Cobalt irradiation: Cobalt irradiation of the small bowel can decrease gastrointestinal (GI) absorption of vitamin B₁₂.

• Colchicine: Colchicine in doses of 1.9 to 3.9mg/day can disrupt normal intestinal mucosal function, leading to malabsorption of several nutrients, including vitamin B₁₂. Lower doses do not seem to have a significant effect on vitamin B₁₂ absorption after 3 years of colchicine therapy. The significance of this interaction is unclear. Vitamin B₁₂ levels should be monitored in people taking large doses of colchicine for prolonged periods.

• Colestipol (Colestid®), Cholestyramine (Questran®): These resins used for sequestering bile acids in order to decrease cholesterol, can decrease gastrointestinal (GI) absorption of vitamin B₁₂. It is unlikely that this interaction will deplete body stores of vitamin B₁₂ unless there are other factors contributing to deficiency. In a group of children treated with cholestyramine for up to 2.5 years there was not any change in serum vitamin B₁₂ levels. Routine supplements are not necessary.

• H₂-receptor antagonists: include cimetidine (Tagamet®), famotidine (Pepcid®), nizatidine (Axid®), and ranitidine (Zantac®). Reduced secretion of gastric acid and pepsin produced by H₂ blockers can reduce absorption of protein-bound (dietary) vitamin B₁₂, but not of supplemental vitamin B₁₂. Gastric acid is needed to release vitamin B₁₂ from protein for absorption. Clinically significant vitamin B₁₂ deficiency and megaloblastic anemia are unlikely, unless H₂ blocker therapy is prolonged (2 years or more), or the person's diet is poor. It is also more likely if the person is rendered achlorhydric (with complete absence of gastric acid secretion), which occurs more frequently with proton pump inhibitors than H₂ blockers. Vitamin B₁₂ levels should be monitored in people taking high doses of H₂ blockers for prolonged periods.

• Metformin (Glucophage®): Metformin may reduce serum folic acid and vitamin B₁₂ levels. These changes can lead to hyperhomocysteinemia, adding to the risk of cardiovascular disease in people with diabetes.^{[citation needed]} There are also rare reports of megaloblastic anemia in people who have taken metformin for 5 years or more. Reduced serum levels of vitamin B₁₂ occur in up to 30% of people taking metformin chronically.^[37][38] However, clinically significant deficiency is not likely to develop if dietary intake of vitamin B₁₂ is adequate. Deficiency can be corrected with vitamin B₁₂ supplements even if metformin is continued. The metformin-induced malabsorption of vitamin B₁₂ is reversible by oral calcium supplementation.^[39] The general clinical significance of metformin upon B₁₂ levels is as yet unknown.^[40]

• Neomycin: Absorption of vitamin B₁₂ can be reduced by neomycin, but prolonged use of large doses is needed to induce pernicious anemia. Supplements are not usually needed with normal doses.

• Nicotine: Nicotine can reduce serum vitamin B₁₂ levels. The need for vitamin B₁₂ supplementation has not been adequately studied.

• Nitrous oxide: Nitrous oxide inactivates the cobalamin form of vitamin B₁₂ by oxidation. Symptoms of vitamin B₁₂ deficiency, including sensory neuropathy, myelopathy, and encephalopathy, can occur within days or weeks of exposure to nitrous oxide anesthesia in people with subclinical vitamin B₁₂ deficiency. Symptoms are treated with high doses of vitamin B₁₂, but recovery can be slow and incomplete. People with normal vitamin B₁₂ levels have sufficient vitamin B₁₂ stores to make the effects of nitrous oxide insignificant, unless exposure is repeated and prolonged (such as recreational use). Vitamin B₁₂ levels should be checked in people with risk factors for vitamin B₁₂ deficiency prior to using nitrous oxide anesthesia.

• Phenytoin (Dilantin®), phenobarbital, primidone (Mysoline®): These anticonvulsants have been associated with reduced vitamin B₁₂ absorption, and reduced serum and cerebrospinal fluid levels in some patients. This may contribute to the megaloblastic anemia, primarily caused by folate deficiency, associated with these drugs. It's also suggested that reduced vitamin B₁₂ levels may contribute to the neuropsychiatric side effects of these drugs. Patients should be encouraged to maintain adequate dietary vitamin B₁₂ intake. Folate and vitamin B₁₂ status should be checked if symptoms of anemia develop.

• Proton pump inhibitors (PPIs): The PPIs include omeprazole (Prilosec®, Losec®), lansoprazole (Prevacid®), rabeprazole (Aciphex®), pantoprazole (Protonix®, Pantoloc®), and esomeprazole (Nexium®). The reduced secretion of gastric acid and pepsin produced by PPIs can reduce absorption of protein-bound (dietary) vitamin B₁₂, but not supplemental vitamin B₁₂. Gastric acid is needed to release vitamin B₁₂ from protein for absorption. Reduced vitamin B₁₂ levels may be more common with PPIs than with H2-blockers, because they are more likely to produce achlorhydria (complete absence of gastric acid secretion). However, clinically significant vitamin B₁₂ deficiency is unlikely, unless PPI therapy is prolonged (2 years or more) or dietary vitamin intake is low. Vitamin B₁₂ levels should be monitored in people taking high doses of PPIs for prolonged periods.

• Zidovudine (AZT, Combivir®, Retrovir®): Reduced serum vitamin B₁₂ levels may occur when zidovudine therapy is started. This adds to other factors that cause low vitamin B₁₂ levels in people with HIV, and might contribute to the hematological toxicity associated with zidovudine. However, data suggests vitamin B₁₂ supplements are not helpful for people taking zidovudine.

Grain alcohol redirects here. ... Aminosalicylic acid (C7H7NO3) is also known as para-aminosalicylic acid, p-aminosalicylic acid or 4-aminosalicylic acid; abbreviated 4-ASA, PAS or P. It is sold in the US by Jacobus Pharmaceutical as Paser®. 5-aminosalicylic acid is a closely related compound that also has medical uses. ... An antibiotic is a drug that kills or slows the growth of bacteria. ... Metronidazole (INN) (IPA: ) is a nitroimidazole anti-infective drug used mainly in the treatment of infections caused by susceptible organisms, particularly anaerobic bacteria and protozoa. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... Oral contraceptives are contraceptives which are taken orally and inhibit the bodys fertility by chemical means. ... Chloramphenicol is a bacteriostatic antibiotic originally derived from the bacterium Streptomyces venezuelae, isolated by David Gottlieb, and introduced into clinical practice in 1949. ... Reticulocyte Erythrocyte Reticulocytes are immature red blood cells, typically comprising about 1% of the red cells in the human body. ... Schematics of shorthand for complete blood count commonly used by physicians. ... This does not cite its references or sources. ... This does not cite its references or sources. ... Diagram showing the small intestine In biology the small intestine is the part of the gastrointestinal tract between the stomach and the large intestine (colon). ... Colchicine is a highly deadly poisonous alkaloid, originally extracted from plants of the genus Colchicum (Autumn crocus, also known as the Meadow saffron). Originally used to treat rheumatic complaints and especially gout, it was also prescribed for its cathartic and emetic effects. ... Malabsorption is the state of impaired absorption of nutrients in the small intestine. ... Link title {{portal|Food} A nutrient is either a chemical element or compound used in an organisms metabolism or physiology. ... Cholestyramine (Questran®, Questran Light®, Cholybar®) is a bile acid sequestrant, which binds bile in the gastrointestinal tract to prevent its reabsorption. ... Insect trapped in resin. ... In pharmacology, bile acid sequestrants a group of medication used for binding bile in the gastrointestinal tract. ... Cholesterol is a sterol (a combination steroid and alcohol) and a lipid found in the cell membranes of all body tissues, and transported in the blood plasma of all animals. ... An H2-receptor antagonist, often shortened to H2 antagonist, is a drug used to block the action of histamine on parietal cells in the stomach, decreasing acid production by these cells. ... Cimetidine is a histamine H2-receptor antagonist that inhibits the production of acid in the stomach. ... Famotidine is a histamine H2-receptor antagonist that inhibits stomach acid production, and is commonly used in the treatment of peptic ulcer disease (PUD) and gastroesophageal reflux disease (GERD). ... Nizatidine is a histamine H2-receptor antagonist that inhibits stomach acid production, and commonly used in the treatment of peptic ulcer disease (PUD) and gastroesophageal reflux disease (GERD). ... Ranitidine (INN) (IPA: ) is a histamine H2-receptor antagonist that inhibits stomach acid production, and commonly used in the treatment of peptic ulcer disease (PUD) and gastroesophageal reflux disease (GERD). ... Gastric acid is, together with several enzymes and the intrinsic factor, one of the main secretions of the stomach. ... Pepsin is a digestive protease (EC 3. ... Achlorhydria or hypochlorhydria is decreased production of gastric acid by the stomach. ... Metformin (INN; trade names Glucophage, Diabex, Diaformin, Fortamet, Riomet, Glumetza and others) is an anti-diabetic drug from the biguanide class of oral hypoglycemic agents. ... Hyperhomocysteinemia is a medical condition characterized by an abnormally large level of homocysteine in the blood. ... This article is about the disease that features high blood sugar. ... Neomycin is an aminoglycoside antibiotic that is found in many topical medications such as creams, ointments and eyedrops. ... Nicotine is an alkaloid found in the nightshade family of plants (Solanaceae), predominantly in tobacco, and in lower quantities in tomato, potato, eggplant (aubergine), and green pepper. ... R-phrases S-phrases Supplementary data page Structure and properties n, εr, etc. ... Neuropathy, strictly speaking, is any disease that affects the nervous system. ... Spinal cord injury, or myelopathy, is a disturbance of the spinal cord that results in loss of sensation and mobility. ... Encephalopathy literally means disease of the brain. ... Anesthesia or anaesthesia (see spelling differences) has traditionally meant the condition of having the perception of pain and other sensations blocked. ... Phenytoin sodium (marketed as Dilantin® in the USA and as Epanutin® in the UK, by Parke-Davis, now part of Pfizer) is a commonly used antiepileptic. ... Phenobarbital (also phenobarbitone) (Luminal®) is a weak acid with the chemical formula C12H12N2O3. ... Primidone, is an anticonvulsant of the pyrimidinedione class whose active metabolites, phenobarbital (minor) and phenylethylmalonamide (PEMA) (major), are also anticonvulsants. ... The anticonvulsants, sometimes also called antiepileptics, belong to a diverse group of pharmaceuticals used in prevention of the occurrence of epileptic seizures. ... Cerebrospinal fluid (CSF), Liquor cerebrospinalis, is a clear bodily fluid that occupies the subarachnoid space in the brain (the space between the skull and the cerebral cortex—more specifically, between the arachnoid and pia layers of the meninges). ... Proton pump inhibitors (or PPIs) are a group of drugs whose main action is pronounced and long-lasting reduction of gastric acid production. ... Omeprazole (INN) (IPA: ) is a proton pump inhibitor (brand names Antra® in Italy) used in the treatment of dyspepsia, peptic ulcer disease (PUD), gastroesophageal reflux disease (GORD/GERD) and Zollinger-Ellison syndrome. ... Lansoprazole, marketed as Takepron (in Japan), Prevacid and Zoton, is a proton pump inhibitor which prevents the stomach from producing acid. ... Rabeprazole is an antiulcer drug in the class of proton pump inhibitors. ... Pantoprazole (brand names Pantopan® in Italy; Protium®; Protonix®; Pantozol®; Pantor®; Pantoloc®; Astropan) is a proton pump inhibitor drug used for short-term treatment of erosion and ulceration of the esophagus caused by gastroesophageal reflux disease. ... Esomeprazole is a proton pump inhibitor used in the treatment of dyspepsia, peptic ulcer disease (PUD), GERD and Zollinger-Ellison syndrome. ... Pepsin is a digestive protease (EC 3. ... Zidovudine (INN) or azidothymidine (AZT) (also called ZDV) is an antiretroviral drug, the first one approved for treatment of HIV. It is also sold under the names Retrovir® and Retrovis®, and as an ingredient in Combivir® and Trizivir®. It is an analog of thymidine. ... Species Human immunodeficiency virus 1 Human immunodeficiency virus 2 Human immunodeficiency virus (HIV) is a retrovirus that causes acquired immunodeficiency syndrome (AIDS, a condition in humans in which the immune system begins to fail, leading to life-threatening opportunistic infections). ...

Interactions with herbs and dietary supplements

• Folic acid: Folic acid, particularly in large doses, can mask vitamin B₁₂ deficiency. In vitamin B₁₂ deficiency, folic acid can produce hematologic improvement in megaloblastic anemia, while allowing potentially irreversible neurological damage to progress. Vitamin B₁₂ status should be determined before folic acid is given as monotherapy.

• Potassium: Potassium supplements can reduce absorption of vitamin B₁₂ in some people. This effect has been reported with potassium chloride and, to a lesser extent, with potassium citrate. Potassium might contribute to vitamin B₁₂ deficiency in some people with other risk factors, but routine supplements are not necessary.

Folic acid and folate (the anion form) are forms of the water-soluble Vitamin B9. ... General Name, Symbol, Number potassium, K, 19 Chemical series alkali metals Group, Period, Block 1, 4, s Appearance silvery white Standard atomic weight 39. ...

References

Year 2007 (MMVII) is now the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 182nd day of the year (183rd in leap years) in the Gregorian calendar. ... For the Manfred Mann album, see 2006 (album). ... is the 157th day of the year (158th in leap years) in the Gregorian calendar. ... For the Manfred Mann album, see 2006 (album). ... is the 253rd day of the year (254th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is now the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 53rd day of the year in the Gregorian calendar. ... The Physicians Committee for Responsible Medicine (PCRM) is a non-profit organization based in Washington, D.C., that promotes preventive medicine, conducts clinical research, and encourages higher standards for ethics and effectiveness in research. ... Year 2007 (MMVII) is now the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 53rd day of the year in the Gregorian calendar. ...

External links

• Jane Higdon, "Vitamin B12", Micronutrient Information Center, Linus Pauling Institute
• fact sheet at NIH
• Vitamin B12. Medline Plus (National Library of Medicine). Part of it was used for this article (US Government public domain), specially for drug and other interactions.
• Vitamin B₁₂ deficiency article in American Family Physician journal
• Vitamin B₁₂: Vital Nutrient for Good Health at the Weston A. Price Foundation
• MeSH Cyanocobalamin