Nat-B

Mechanism of action

Cyanocobalamin serves as a cofactor for methionine synthase and L-methylmalonyl-CoA mutase enzymes. Methionine synthase is essential for the synthesis of purines and pyrimidines that form DNA. L-methylmalonyl-CoA mutase is involved in the degradation of propionate, crucial for fat and protein metabolism. The lack of vitamin B12 results in the accumulation of methylmalonyl CoA, contributing to neurological manifestations. Additionally, it is vital for the synthesis of methionine from homocysteine, and its deficiency can lead to functional folate deficiency, which impacts red blood cell formation.

Pharmacodynamics

Cyanocobalamin corrects vitamin B12 deficiency and alleviates symptoms and laboratory abnormalities associated with pernicious anemia, such as megaloblastic indices, gastrointestinal lesions, and neurological damage. It is essential for growth, cell reproduction, hematopoiesis, nucleoprotein, and myelin synthesis. The drug significantly impacts fat and carbohydrate metabolism, as well as protein synthesis. Rapidly dividing cells, such as those in the bone marrow, have a high demand for vitamin B12. Parenteral administration of cyanocobalamin can quickly reverse the anemia and gastrointestinal symptoms of vitamin B12 deficiency, while also preventing the progression of related neurological damage.

Pharmacokinetics

Cyanocobalamin is absorbed in the intestine, primarily in the ileum, via specific transport mechanisms that may be impaired in individuals with intrinsic factor deficiency (as seen in pernicious anemia). Once absorbed, it is widely distributed in body tissues, with significant concentrations found in the liver, kidneys, and heart. The vitamin is stored in the liver, where it can be released into circulation as needed. Cyanocobalamin undergoes conversion to its active forms, methylcobalamin and adenosylcobalamin, which are utilized in various metabolic processes. The elimination half-life is variable, but it is generally excreted via urine as metabolites

Adverse effects

• Abdominal distension
• Decreased appetite
• Flatulence
• Nausea

Interactions

• Folic acid may interact with cyanocobalamin, especially in cases of megaloblastic anemia caused by folate deficiency.

Precautions

• Should not be given alone for pernicious anemia.
• Use caution in patients with Leber's disease, as it may worsen optic atrophy.

Pregnancy

Cyanocobalamin is essential during pregnancy as it helps prevent neural tube defects. It is advised that females of childbearing potential take 5 mg of folic acid daily before conception and throughout pregnancy.

Breast-feeding

Cyanocobalamin is generally considered safe during breastfeeding, but it is advised to monitor the infant for any adverse effects.

Storage

Store in a cool, dry place, away from direct sunlight. Protect from moisture.

Formulations

• Tablet: 1000 micrograms
• Tablet: 500 micrograms
• Tablet: 100 micrograms
• Oral solution: 50 micrograms per ml
• Solution for injection: 1000 micrograms per ml

Indications

• Vitamin B6 deficiency
• Isoniazid-induced neuropathy (prophylaxis and treatment)
• Idiopathic sideroblastic anaemia
• Prevention of penicillamine-induced neuropathy in Wilson's disease
• Metabolic diseases such as cystathioninuria and homocystinuria
• Premenstrual syndrome

Mechanism of action

Pyridoxine hydrochloride is converted in the body to pyridoxal phosphate, which is the active form of vitamin B6. It serves as a cofactor for more than 100 enzymatic reactions, particularly those involved in the metabolism of amino acids, the synthesis of neurotransmitters (such as serotonin, dopamine, and gamma-aminobutyric acid), and the production of hemoglobin. Its role in neurotransmitter synthesis makes it crucial for normal brain function and mood regulation.

Pharmacodynamics

Pyridoxine hydrochloride exerts its effects by facilitating the conversion of amino acids into neurotransmitters and is involved in the synthesis of heme. It impacts the metabolism of tryptophan to serotonin and is essential for the production of norepinephrine and gamma-aminobutyric acid, which are vital for proper neurological function. Deficiency of vitamin B6 can lead to neurological symptoms, including peripheral neuropathy and cognitive disturbances.

Pharmacokinetics

Pyridoxine hydrochloride is readily absorbed from the gastrointestinal tract. It is primarily metabolized in the liver, where it is converted to its active form, pyridoxal phosphate. The elimination half-life of pyridoxine is approximately 15-20 days, and it is excreted primarily through the urine. Renal impairment may affect the metabolism and excretion of pyridoxine, necessitating dose adjustments.

Contra-indications

• Hyperkalaemia
• Severe liver damage

Adverse effects

• Peripheral neuritis
• Hepatitis
• Hypoglycaemia
• Urine discolouration

Interactions

• Potassium aminobenzoate
• Isoniazid

Precautions

• Caution in renal impairment (increased risk of hyperkalaemia)
• Interrupt treatment during periods of low food intake (such as fasting, anorexia, and nausea) to reduce risk of hypoglycaemia
• Monitor liver function tests monthly during high-dose therapy

Pregnancy

Manufacturer advises avoiding use in pregnancy due to potential risk of birth defects; however, no adverse effects have been reported at normal dietary levels.

Breast-feeding

Theoretical risk of toxicity in infants if mothers take large doses.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Formulations

• Pyridoxine hydrochloride 10 mg tablets
• Pyridoxine hydrochloride 20 mg tablets
• Pyridoxine hydrochloride 50 mg tablets
• Pyridoxine hydrochloride oral solution 20 mg per 1 ml

Indications

• Isolated carboxylase defects
• Defects of biotin metabolism
• Prevention of deficiency in complete biliary obstruction

Dosage

Children: Neonate: Initially 10 mg once daily, adjusted according to response; maintenance 5–20 mg daily. Child: Initially 10 mg once daily, adjusted according to response; maintenance 5–20 mg daily, higher doses may be required.

Adults: For adults, the dosing may vary based on the condition being treated. General guidance is to refer to the BNF for specific dosing recommendations.

Mechanism of action

Biotin acts as a coenzyme for carboxylase enzymes, facilitating critical metabolic processes including gluconeogenesis, fatty acid synthesis, and amino acid catabolism.

Pharmacodynamics

Biotin is essential for the carboxylation of substrates in metabolic pathways, influencing energy metabolism and the synthesis of important biomolecules. It supports normal growth and development.

Pharmacokinetics

Biotin is absorbed in the intestine and is widely distributed in body tissues. It is not stored in large amounts, with excess being excreted in urine. The half-life and specific pharmacokinetic parameters can vary based on individual metabolism and dietary intake.

Adverse effects

• Rough skin
• Dry hair
• Enlarged liver
• Increases in erythrocyte sedimentation rate
• Increased serum calcium
• Increased serum alkaline phosphatase concentration

Precautions

• Excessive doses may be teratogenic
• High levels of vitamin A may cause birth defects

Pregnancy

No information available.

Breast-feeding

No information available.

Formulations

• Tablet
• Oral suspension
• Oral solution
• Solution for injection

Indications

• Papulopustular rosacea
• Inflammatory acne vulgaris

Dosage

Children: Refer to the BNF for Children for specific dosing recommendations.

Adults: For papulopustular rosacea, apply daily for up to 4 months. The treatment course may be repeated; discontinue if no improvement is observed after 3 months. For inflammatory acne vulgaris, apply twice daily, reduced to once daily or alternate days if irritation occurs.

Mechanism of action

Nicotinamide exhibits anti-inflammatory effects by inhibiting the release of pro-inflammatory cytokines and enhancing the barrier function of the skin. It is also involved in the NAD salvage pathway, which is essential for maintaining cellular energy levels and promoting cell repair mechanisms. Additionally, nicotinamide contributes to the synthesis of coenzymes involved in metabolic processes, including the conversion of niacin into NAD+.

Pharmacodynamics

Nicotinamide is known for its ability to improve skin hydration and reduce transepidermal water loss. It has been shown to decrease the appearance of acne lesions and rosacea by modulating inflammatory responses and accelerating cell turnover. Its antioxidant properties also help to protect the skin from oxidative stress and UV damage.

Pharmacokinetics

When applied topically, nicotinamide is absorbed through the skin layers, with minimal systemic absorption. Its peak plasma concentrations are generally low, and the drug has a half-life that varies depending on the route of administration. The metabolism of nicotinamide occurs primarily in the liver, where it is converted into its active forms, including NAD+. The elimination route is via the kidneys, with metabolites excreted in urine.

Contra-indications

• Pregnancy
• Severe acne involving large areas
• Severe skin reactions

Adverse effects

• Sunburn
• Skin reactions (common or very common)
• Cheilitis
• Eyelid oedema
• Flushing
• Dry skin
• Eye irritation
• Photosensitivity reactions
• Transient skin pigmentation changes

Interactions

• Clindamycin
• Topical retinoids
• Abrasive cleaners
• Comedogenic cosmetics

Precautions

• Avoid exposure to UV light, including sunlight and sunlamps
• Wash hands immediately after use
• Avoid contact with eyes and mucous membranes
• Use moisturizers to reduce the risk of skin irritation
• Discontinue treatment if severe irritation occurs

Pregnancy

Avoid use during pregnancy due to potential risks, as limited information is available regarding toxicity.

Breast-feeding

Amount of drug in milk after topical application is probably too small to be harmful; ensure infant does not come in contact with treated areas.

Storage

Store at room temperature away from moisture and light.

Formulations

• Cream
• Gel

Indications

• Vitamin B2 deficiency
• Isoniazid-induced neuropathy (prophylaxis and treatment)
• Metabolic diseases
• Cystathioninuria
• Homocystinuria
• Wilson's disease
• Prevention of penicillamine-induced neuropathy

Mechanism of action

Riboflavin acts as a precursor to flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), which are essential coenzymes in various enzymatic reactions. It binds to riboflavin hydrogenase, riboflavin kinase, and riboflavin synthase, facilitating the production of FMN and FAD. These coenzymes are critical for normal tissue respiration and energy metabolism, influencing hydrogen transport in oxidative enzyme systems such as cytochrome C reductase and succinic dehydrogenase. Moreover, riboflavin contributes to the antioxidant activity by aiding in the production of reduced glutathione, a key antioxidant in the body.

Pharmacodynamics

Riboflavin is an easily absorbed, water-soluble micronutrient that supports energy production by assisting in the metabolism of fats, carbohydrates, and proteins. It is vital for red blood cell formation, antibody production, and regulating growth and reproduction. The vitamin plays a significant role in maintaining healthy skin, nails, and hair, as well as supporting thyroid activity. Riboflavin also has therapeutic implications in preventing or treating various eye disorders, including cataracts.

Pharmacokinetics

Riboflavin is rapidly absorbed in the gastrointestinal tract, with its bioavailability influenced by dietary intake. It is primarily excreted through urine, with excess intake leading to bright yellow urine, which is a harmless side effect. The vitamin does not accumulate in the body, necessitating regular dietary intake to maintain adequate levels.

Adverse effects

• Urine discolouration
• Peripheral neuritis

Precautions

• With intravenous use, risk of cardiovascular collapse; resuscitation facilities must be available and monitor closely.

Pregnancy

Crosses the placenta but no adverse effects reported; information at high doses limited.

Breast-feeding

Present in breast milk but no adverse effects reported; information at high doses limited.

Storage

Store in a cool, dry place away from direct sunlight.

Formulations

• 100 mg modified-release tablets
• 50 mg capsules
• 100 mg capsules
• 100 mg tablets
• Oral solution

Indications

• Vitamin B1 deficiency
• Wernicke-Korsakoff syndrome
• Beriberi
• Isoniazid-induced neuropathy (prophylaxis and treatment)
• Severe depletion or malabsorption of vitamins B and C

Dosage

Adults: For vitamin deficiency: 25–100 mg daily. For severe deficiency: 200–300 mg daily in divided doses. For

Mechanism of action

Thiamine functions primarily as a precursor for several phosphorylated active forms, which act as coenzymes in metabolic pathways. It reduces intracellular protein glycation by redirecting glycolytic flux and supports the synthesis of nucleic acids necessary for cell survival and proliferation. Additionally, thiamine has been shown to inhibit glucose-induced proliferation of endothelial cells, thus possibly playing a role in the modulation of vascular health.

Pharmacodynamics

Thiamine exhibits antioxidant properties and contributes to erythropoiesis, cognitive function, and mood regulation. It has protective effects against oxidative stress, particularly in neuronal tissues, where deficiency can lead to neuronal death due to increased free radical production. Thiamine also modulates glucose metabolism, influencing smooth muscle cell proliferation and potentially impacting the progression of atherosclerosis.

Pharmacokinetics

Thiamine is rapidly absorbed from the gastrointestinal tract, primarily in the jejunum, and is distributed throughout the body, with higher concentrations found in the liver, heart, and brain. It is excreted in urine, and its half-life is relatively short. The vitamin is converted into active forms within tissues, including thiamine diphosphate (TDP), which is the coenzyme form involved in carbohydrate metabolism. The body does not store significant amounts of thiamine, making regular dietary intake essential.

Adverse effects

• Allergic reactions
• Anaphylaxis (rare)
• Gastrointestinal disturbances

Precautions

• Facilities for treating anaphylaxis should be available when parenteral thiamine is administered
• Use with caution in patients with a history of hypersensitivity to thiamine

Pregnancy

Thiamine crosses the placenta but no adverse effects have been reported. Information regarding high doses is limited.

Breast-feeding

Severely thiamine-deficient mothers should avoid breast-feeding as thiamine is present in breast milk.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Formulations

• Thiamine hydrochloride 20 mg/ml oral solution
• Thiamine hydrochloride 50 mg tablets
• Thiamine hydrochloride 100 mg modified-release tablets
• Thiamine hydrochloride oral suspension

Dosage

Children: Refer to specific product formulation guidelines as bitartarate does not have a standardized dosage. Its use is primarily as an excipient.

Adults: Refer to specific product formulation guidelines as bitartarate does not have a standardized dosage. Its use is primarily as an excipient.

Mechanism of action

Bitartarate exhibits its effects through the modulation of pH levels in solutions, which can influence the solubility and bioavailability of certain drugs. It does not have a direct pharmacological effect on biological systems but serves as a supportive component in drug formulations.

Pharmacodynamics

Bitartarate does not exhibit intrinsic pharmacodynamic activity as it functions primarily as an excipient. Its role in influencing the stability and solubility of active pharmaceutical ingredients can indirectly affect the pharmacodynamics of the drugs it accompanies, potentially enhancing their efficacy.

Pharmacokinetics

Bitartarate is not typically absorbed systemically as it is used in formulations rather than as an active pharmaceutical agent. Its pharmacokinetics are not well defined, as it primarily serves a supportive role in drug delivery systems, thus it does not have pharmacokinetic parameters such as absorption, distribution, metabolism, or excretion in the traditional sense.

Pregnancy

Bitartarate should only be used during pregnancy if the potential benefit justifies the potential risk to the fetus. Consult healthcare professionals for specific advice.

Breast-feeding

It is not known whether bitartarate is excreted in human milk. Caution is advised when administering to breastfeeding mothers.

Storage

Store at room temperature, away from moisture and light. Keep out of reach of children.

Indications

• Choline deficiency
• Support in liver function
• Neurological health, including cognitive function
• Fat metabolism disorders

Dosage

Children: Refer to the BNF for Children for specific dosing guidelines.

Adults: Refer to the BNF for specific dosing guidelines.

Mechanism of action

Choline is a major component of phosphatidylcholine, which is essential for maintaining cell membrane integrity, facilitating information flow, and intracellular communication. It is involved in the synthesis of acetylcholine, a key neurotransmitter in the central nervous system. Choline deficiency can lead to apoptosis by affecting cell membrane composition and increasing ceramide levels, which activates apoptotic pathways. Additionally, choline is a precursor to betaine, which helps regulate homocysteine levels, thus reducing cardiovascular risks.

Pharmacodynamics

Choline is crucial for proper nerve conduction in the central nervous system as it is a precursor for acetylcholine. It supports liver function, gallbladder regulation, and lipid metabolism. Adequate choline levels are associated with the prevention of excessive fat accumulation in the liver and may mitigate conditions such as Parkinsonism and tardive dyskinesia. Deficiencies can lead to serious health problems, including liver dysfunction and stunted growth.

Pharmacokinetics

Choline is absorbed in the intestines and distributed throughout the body, where it is utilized in various metabolic pathways. The liver plays a central role in choline metabolism, converting it into phosphatidylcholine and other metabolites. The half-life and excretion pathways of choline are not well defined but are influenced by dietary intake, physiological state, and individual metabolism.

Interactions

• corticosteroids+cholinesalicylate: Unknown (decreases concentration)

Pregnancy

Choline is generally considered safe during pregnancy, as it is essential for fetal development, particularly for brain development and function. However, it is important to adhere to recommended dietary allowances.

Breast-feeding

Choline is important during breastfeeding as it supports infant brain development. Adequate intake is recommended for nursing mothers.

Storage

Store in a cool, dry place, away from direct sunlight and moisture. Keep out of reach of children.

Mechanism of action

Folic acid is biochemically inactive until it is converted into active forms, primarily tetrahydrofolic acid and methyltetrahydrofolate, by the enzyme dihydrofolate reductase (DHFR). These active forms are essential for maintaining normal erythropoiesis, synthesizing nucleic acids, interconverting amino acids, and generating formate. They participate in critical one-carbon transfer reactions necessary for DNA synthesis and methylation processes. Folic acid, in conjunction with vitamin B12, helps normalize elevated homocysteine levels by facilitating its remethylation to methionine, a process that is crucial for various metabolic pathways.

Pharmacodynamics

Folic acid is an essential cofactor for enzymes involved in nucleic acid synthesis and amino acid metabolism. It is particularly significant in preventing megaloblastic anemia, which arises from impaired DNA synthesis due to folate deficiency. The synthesis of thymidylate, necessary for DNA formation, is directly influenced by folate availability. Folic acid's role is especially crucial during periods of rapid cellular division, and it has protective effects against certain cancer developments. As humans cannot synthesize folic acid endogenously, adequate dietary intake is essential for maintaining normal physiological functions.

Pharmacokinetics

Folic acid is absorbed in the small intestine and is then converted into its active forms within the body. The bioavailability of folic acid is influenced by factors such as food composition and the presence of certain gastrointestinal conditions. Once absorbed, it is transported in the bloodstream, mainly as 5-methyltetrahydrofolate. The distribution of folate occurs within various tissues, with significant

Adverse effects

• Allergic reactions
• Gastrointestinal disturbances
• Skin rash
• Altered sleep patterns

Interactions

• Anticonvulsants may reduce the effectiveness of folic acid
• Methotrexate may interfere with folic acid metabolism
• Trimethoprim-sulfamethoxazole can enhance the effects of folic acid deficiency

Precautions

• Monitor for signs of anemia in patients with malabsorption syndromes
• Use cautiously in patients with a history of hypersensitivity to folic acid
• Assess for vitamin B12 deficiency before initiating treatment, as folic acid can mask symptoms

Pregnancy

Folic acid is essential during pregnancy to prevent neural tube defects and support fetal development. Supplementation is recommended before conception and during the first trimester.

Breast-feeding

Folic acid passes into breast milk, and adequate maternal intake is important to ensure sufficient levels for the nursing infant.

Storage

Store in a cool, dry place away from light. Keep out of reach of children.

Formulations

• Tablets
• Oral solutions
• Injectable forms

Indications

• Dehydration
• Electrolyte imbalance
• Heat-related illnesses
• Postoperative recovery
• Diarrhea and vomiting
• Chronic illnesses leading to fluid loss

Dosage

Children: Pediatric dosing should be guided by clinical guidelines and the severity of dehydration. For children experiencing mild to moderate dehydration, ORS is recommended, with the amount based on weight and age. For severe dehydration, intravenous fluid therapy is indicated, with specific protocols available in pediatric guidelines.

Adults: Dosage varies based on the degree of dehydration and the underlying clinical condition. For mild dehydration, oral rehydration solutions (ORS) are often sufficient, while severe cases may require intravenous fluids, with specific rates and types determined by clinical judgment.

Mechanism of action

Hydration works by replenishing lost fluids and electrolytes, restoring osmotic balance and cellular function. The primary components of hydration solutions, such as water, electrolytes (sodium, potassium, chloride), and sometimes glucose, promote proper cellular hydration and support metabolic processes.

Pharmacodynamics

The pharmacodynamics of hydration primarily involves the restoration of plasma volume and the maintenance of electrolyte homeostasis. Proper hydration enhances kidney function, improves cardiovascular stability, and supports normal physiological functions, such as thermoregulation and nutrient transport. It also aids in the recovery of tissues and organs affected by dehydration.

Pharmacokinetics

The pharmacokinetics of hydration solutions depend on the composition of the fluid administered. Oral hydration solutions are absorbed primarily in the gastrointestinal tract, with the rate of absorption influenced by the concentration of electrolytes and glucose. Intravenous fluids can distribute rapidly into the extracellular space, with effects seen almost immediately. The elimination of excess fluids occurs mainly through renal excretion.

Pregnancy

Hydration is essential during pregnancy, but fluid intake should be monitored to avoid excessive hydration, which can lead to complications.

Breast-feeding

Adequate hydration is important during breastfeeding, as it supports milk production. However, excessive fluid intake should be avoided.

Storage

Store in a cool, dry place away from direct sunlight.

Formulations

• Oral solutions
• Intravenous fluids
• Electrolyte solutions

Indications

• Polycystic ovary syndrome (PCOS)
• Generalized anxiety disorder
• Depression
• Obsessive-compulsive disorder
• Insulin resistance

Dosage

Children: Refer to the BNF for Children for appropriate dosing guidelines for paediatric patients.

Adults: Refer to the BNF for specific dosing recommendations, as doses may vary based on the condition being treated.

Mechanism of action

Inositol functions primarily as a precursor for the synthesis of phosphoinositides, which are key components of cell membranes. These phosphoinositides are involved in various intracellular signaling pathways, particularly those mediated by G-protein coupled receptors. Inositol also influences the action of neurotransmitters such as serotonin and has been shown to enhance insulin sensitivity and glucose metabolism.

Pharmacodynamics

Inositol has been observed to have mood-stabilizing effects and may improve insulin sensitivity. Its role in cell signaling impacts various physiological processes, including cellular communication and metabolic regulation. The therapeutic effects of inositol in psychiatric conditions may be attributed to its ability to modulate neurotransmitter systems, particularly involving serotonin and dopamine.

Pharmacokinetics

Inositol is well-absorbed from the gastrointestinal tract, with peak plasma levels occurring within 1 to 2 hours after ingestion. It is distributed throughout the body and can cross the blood-brain barrier. Inositol is predominantly excreted in the urine, with a half-life that varies based on dosage and individual metabolism. Metabolism occurs primarily through dephosphorylation to form various inositol phosphates.

Pregnancy

Inositol is generally considered safe during pregnancy but should be used under medical supervision.

Breast-feeding

Inositol is likely safe during breastfeeding, but consult a healthcare provider for specific recommendations.

Storage

Store in a cool, dry place, away from direct sunlight. Keep out of reach of children.

Formulations

• Powder
• Capsules

Indications

• Pantothenate deficiency
• Support in energy metabolism
• Adjuvant therapy in chronic conditions requiring enhanced energy production

Dosage

Children: Refer to the BNF for Children for paediatric dosing recommendations.

Adults: Refer to the BNF for specific dosing information, generally 5-10 mg daily for adults.

Mechanism of action

Pantothenate functions primarily as a precursor to coenzyme A (CoA), which is vital for various biochemical reactions in the body. CoA is involved in the metabolism of fatty acids, the synthesis of cholesterol and steroid hormones, and the acetylation of various substrates, which is crucial for energy production and metabolic processes.

Pharmacodynamics

Pantothenate plays a significant role in energy metabolism, cellular respiration, and the biosynthesis of fatty acids. It facilitates the transfer of acyl groups, which is critical for the metabolism of carbohydrates and fats, thereby influencing the overall energy production in cells. Adequate levels of pantothenate are necessary for maintaining metabolic homeostasis and supporting growth and development.

Pharmacokinetics

Pantothenate is well absorbed from the gastrointestinal tract, with a bioavailability of approximately 70%. Once absorbed, it is widely distributed throughout the body, particularly in the liver, adrenal glands, and kidneys. The vitamin is metabolized primarily in the liver, where it is converted to coenzyme A. Excess pantothenate is excreted in the urine as pantothenic acid and its metabolites. The half-life of pantothenate in the body is not well-defined but is generally considered to be relatively short due to its water-soluble nature.

Pregnancy

Pantothenic acid (Vitamin B5) is generally regarded as safe during pregnancy. It is important to maintain adequate levels for fetal development.

Breast-feeding

Pantothenic acid is excreted in breast milk in small amounts. Adequate intake is important for breastfeeding mothers, but supplementation is typically not necessary.

Storage

Store in a cool, dry place, away from light. Keep out of reach of children.

Formulations

• Pantothenate tablets
• Pantothenic acid capsules
• Pantothenate injections

Indications

• Vitamin B6 deficiency
• Peripheral neuropathy associated with isoniazid therapy
• Supplementation in specific dietary deficiencies

Dosage

Children: Refer to the BNF for Children for specific paediatric dosing guidance.

Adults: Refer to the BNF for specific dosing details, typically 10-50 mg daily for deficiency.

Mechanism of action

Pyridoxine, mainly in its active form pyridoxal 5'-phosphate, is involved in numerous biochemical reactions, including amino acid metabolism, glycogen breakdown, nucleic acid synthesis, and the production of key neurotransmitters. It aids in the synthesis of hemoglobin and sphingolipids, and its deficiency can impair several physiological processes, including immune response and vascular health.

Pharmacodynamics

Pyridoxine is utilized for the prevention and treatment of vitamin B6 deficiency, particularly in individuals undergoing treatment with isoniazid, which can deplete vitamin B6 levels. It may also have beneficial effects on blood pressure and lipid profiles, as studies have shown it can lower both systolic and diastolic blood pressure, inhibit platelet aggregation, and improve cholesterol levels. Additionally, it plays a role in enhancing immune function and protecting endothelial cells from injury.

Pharmacokinetics

Pyridoxine is rapidly absorbed from the gastrointestinal tract. It is transported to tissues where it is phosphorylated to its active form, pyridoxal 5'-phosphate. The vitamin is primarily excreted in urine as pyridoxine and its metabolites. Its half-life varies depending on the individual’s nutritional status and other factors. Adequate dietary intake is essential for maintaining optimal levels in the body.

Pregnancy

Pyridoxine is generally considered safe during pregnancy. However, high doses should be avoided unless specifically prescribed.

Breast-feeding

Pyridoxine is excreted in breast milk, but at normal dietary levels it is considered safe for breastfeeding mothers.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Formulations

• Tablets
• Oral solution
• Injectable form

Indications

• Thiamine deficiency
• Wernicke's encephalopathy
• Beriberi
• Alcoholism-related complications
• Certain metabolic disorders

Dosage

Children: Refer to BNF for Children for appropriate dosing information.

Adults: Refer to established clinical guidelines or BNF for specific dosing recommendations.

Mechanism of action

Thiamine is a coenzyme for several important enzymatic reactions, including the pyruvate dehydrogenase complex and alpha-ketoglutarate dehydrogenase. It is essential for converting carbohydrates into energy, facilitating the metabolism of glucose, and maintaining normal nerve function.

Pharmacodynamics

Thiamine deficiency leads to impaired carbohydrate metabolism, which can result in neurological and cardiovascular dysfunction. Supplementation with thiamine helps restore normal metabolic function and can alleviate symptoms associated with deficiency, such as Wernicke's encephalopathy and Beriberi. It also plays a role in the synthesis of neurotransmitters and in maintaining myelin integrity.

Pharmacokinetics

Thiamine is readily absorbed from the gastrointestinal tract, with peak plasma concentrations occurring within 1-2 hours after oral administration. It is distributed throughout the body, primarily in the liver, kidneys, and heart. Thiamine is metabolized in the liver to its active form, thiamine pyrophosphate. It has a biological half-life of about 9-18 days and is excreted primarily in the urine. Excess thiamine is excreted, making toxicity rare.

Adverse effects

• Allergic reactions
• Hypersensitivity reactions
• Gastrointestinal disturbances

Interactions

• May interact with certain diuretics, leading to altered thiamine levels

Precautions

• Use with caution in patients with renal impairment
• Monitor patients with a history of thiamine deficiency

Pregnancy

Thiamine is considered safe during pregnancy, as it is an essential nutrient.

Breast-feeding

Thiamine is excreted in breast milk, but supplementation is generally considered safe for breastfeeding mothers.

Storage

Store in a cool, dry place away from direct sunlight.

Formulations

• Thiamine hydrochloride injection
• Thiamine hydrochloride oral tablets
• Thiamine hydrochloride oral solution

Mechanism of action

Biotin is necessary for the proper functioning of enzymes that transport carboxyl units and fix carbon dioxide, and is required for various metabolic functions, including gluconeogenesis, lipogenesis, fatty acid biosynthesis, propionate metabolism, and catabolism of branched-chain amino acids. In human tissues biotin is a cofactor for the enzymatic carboxylation of four substrates: pyruvate, acetyl coenzyme A (CoA), propionyl CoA, and beta-methylcrotonyl CoA. As such, it plays an important role in both carbohydrate and fat metabolism. Carbon dioxide fixation occurs in a two-step reaction, the first involving binding of carbon dioxide to the biotin moiety of the holoenzyme, and the second involving transfer of the biotin-bound carbon dioxide to an appropriate acceptor. Biotin functions in carbon dioxide fixation reactions in intermediate metabolism, transferring the carboxyl group to acceptor molecules. It acts similarly in decarboxylation reactions. Biotin is essential in human metabolism for its part in the previously described enzymatic steps, in catalyzing deamination of amino acids, and in oleic acid synthesis. Biotin is a cofactor for the enzymatic carboxylation of pyruvate, acetyl coenzyme A (CoA), propionyl CoA, and beta-methylcrotonyl CoA, and, therefore, plays an important role in carbohydrate and fat metabolism. Protein folding in the endoplasmic reticulum (ER) depends on Ca2+; uptake of Ca2+ into the ER is mediated by sarco/endoplasmic reticulum Ca2+-ATPase 3 (SERCA3). The 5'-flanking region of the SERCA3 gene (ATP2A3) contains numerous binding sites for the transcription factors Sp1 and Sp3. Biotin affects the nuclear abundance of Sp1 and Sp3, which may act as transcriptional activators or repressors. Here we determined whether biotin affects the expression of the SERCA3 gene and, thus, protein folding in human lymphoid cells. Jurkat cells were cultured in media containing 0.025 nmol/L biotin (denoted "deficient") or 10 nmol/L biotin ("supplemented"). The transcriptional activity of the full-length human SERCA3 promoter was 50% lower in biotin-supplemented cells compared to biotin-deficient cells. Biotin-dependent repressors bind to elements located 731 to 1312 bp upstream from the transcription start site in the SERCA3 gene. The following suggest that low expression of SERCA3 in biotin-supplemented cells impaired folding of secretory proteins in the ER, triggering unfolded protein response: (i) sequestration of Ca2+ in the ER decreased by 14 to 24% in response to biotin supplementation; (ii) secretion of interleukin-2 into the extracellular space decreased by 75% in response to biotin supplementation; (iii) the nuclear abundance of stress-induced transcription factors increased in response to biotin supplementation; and (iv) the abundance of stress-related proteins such ubiquitin activating enzyme 1, growth arrest and DNA damage 153 gene, X-box binding protein 1 and phosphorylated eukaryotic translation initiation factor 2alpha increased in response to biotin supplementation. Collectively, this study suggests that supplements containing pharmacological doses of biotin may cause cell stress by impairing protein folding in the ER. Evidence is emerging that biotin participates in processes other than classical carboxylation reactions. Specifically, novel roles for biotin in cell signaling, gene expression, and chromatin structure have been identified in recent years. Human cells accumulate biotin by using both the sodium-dependent multivitamin transporter and monocarboxylate transporter 1. These transporters and other biotin-binding proteins partition biotin to compartments involved in biotin signaling: cytoplasm, mitochondria, and nuclei. The activity of cell signals such as biotinyl-AMP, Sp1 and Sp3, nuclear factor (NF)-kappaB, and receptor tyrosine kinases depends on biotin supply. Consistent with a role for biotin and its catabolites in modulating these cell signals, greater than 2000 biotin-dependent genes have

Pharmacodynamics

Biotin is a water-soluble B-complex vitamin which is composed of an ureido ring fused with a tetrahydrothiophene ring, which attaches a valeric acid substituent at one of its carbon atoms. Biotin is used in cell growth, the production of fatty acids, metabolism of fats, and amino acids. It plays a role in the Kreb cycle, which is the process in which energy is released from food. Biotin not only assists in various metabolic chemical conversions, but also helps with the transfer of carbon dioxide. Biotin is also helpful in maintaining a steady blood sugar level. Biotin is often recommended for strengthening hair and nails. Consequenty, it is found in many cosmetic and health products for the hair and skin. Biotin deficiency is a rare nutritional disorder caused by a deficiency of biotin. Initial symptoms of biotin deficiency include: Dry skin, Seborrheic dermatitis, Fungal infections, rashes including erythematous periorofacial macular rash, fine and brittle hair, and hair loss or total alopecia. If left untreated, neurological symptoms can develop, including mild depression, which may progress to profound lassitude and, eventually, to somnolence; changes in mental status, generalized muscular pains (myalgias), hyperesthesias and paresthesias. The treatment for biotin deficiency is to simply start taking some biotin supplements. A lack of biotin in infants will lead to a condition called seborrheic dermatitis or "cradle cap". Biotin deficiencies are extremely rare in adults but if it does occur, it will lead to anemia, depression, hair loss, high blood sugar levels, muscle pain, nausea, loss of appetite and inflamed mucous membranes.

Mechanism of action

Vitamin B12 serves as a cofactor for _methionine synthase_ and _L-methylmalonyl-CoA mutase_ enzymes. Methionine synthase is essential for the synthesis of purines and pyrimidines that form DNA. L-methylmalonyl-CoA mutase converts L-methylmalonyl-CoA to _succinyl-CoA_ in the degradation of propionate, an important reaction required for both fat and protein metabolism. It is a lack of vitamin B12 cofactor in the above reaction and the resulting accumulation of methylmalonyl CoA that is believed to be responsible for the neurological manifestations of B12 deficiency. Succinyl-CoA is also necessary for the synthesis of hemoglobin. In tissues, vitamin B12 is required for the synthesis of _methionine_ from homocysteine. Methionine is required for the formation of S-adenosylmethionine, a methyl donor for nearly 100 substrates, comprised of DNA, RNA, hormones, proteins, as well as lipids. Without vitamin B12, tetrahydrofolate cannot be regenerated from 5-methyltetrahydrofolate, and this can lead to functional folate deficiency,. This reaction is dependent on methylcobalamin (vitamin B12) as a co-factor and is also dependent on folate, in which the methyl group of methyltetrahydrofolate is transferred to homocysteine to form _methionine_ and _tetrahydrofolate_. Vitamin B12 incorporates into circulating folic acid into growing red blood cells; retaining the folate in these cells. A deficiency of vitamin B12 and the interruption of this reaction leads to the development of megaloblastic anemia.

Pharmacodynamics

**General effects** Cyanocobalamin corrects vitamin B12 deficiency and improves the symptoms and laboratory abnormalities associated with pernicious anemia (megaloblastic indices, gastrointestinal lesions, and neurologic damage). This drug aids in growth, cell reproduction, hematopoiesis, nucleoprotein, and myelin synthesis. It also plays an important role in fat metabolism, carbohydrate metabolism, as well as protein synthesis. Cells that undergo rapid division (for example, epithelial cells, bone marrow, and myeloid cells) have a high demand for vitamin B12. **Parenteral cyanocobalamin effects** The parenteral administration of vitamin B12 rapidly and completely reverses the megaloblastic anemia and gastrointestinal symptoms of vitamin B12 deficiency. Rapid parenteral administration of vitamin B12 in deficiency related neurological damage prevents the progression of this condition. **Nasal spray effects** In 24 vitamin B12 deficient patients who were already stabilized on intramuscular (IM) vitamin B12 therapy, single daily doses of intranasal cyanocobalamin for 8 weeks lead to serum vitamin B12 concentrations that were within the target therapeutic range (>200 ng/L).

Mechanism of action

Binds to riboflavin hydrogenase, riboflavin kinase, and riboflavin synthase. Riboflavin is the precursor of flavin mononucleotide (FMN, riboflavin monophosphate) and flavin adenine dinucleotide (FAD). The antioxidant activity of riboflavin is principally derived from its role as a precursor of FAD and the role of this cofactor in the production of the antioxidant reduced glutathione. Reduced glutathione is the cofactor of the selenium-containing glutathione peroxidases among other things. The glutathione peroxidases are major antioxidant enzymes. Reduced glutathione is generated by the FAD-containing enzyme glutathione reductase. Riboflavin is converted to 2 coenzymes, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), which are necessary for normal tissue respiration. Riboflavin is also required for activation of pyridoxine, conversion of tryptophan to niacin, and may be involved in maintaining erythrocyte integrity. Riboflavin functions as the coenzyme for flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN), which primarily influence hydrogen transport in oxidative enzyme systems (eg, cytochrome C reductase, succinic dehydrogenase, xanthine oxidase). Two active forms of riboflavin exist ... coenzyme flavin mononucleotide (FMN) and coenzyme flavin adenine dinucleotide (FAD). They are formed by reaction of riboflavin with 1 and 2 molecules of ATP as follow: riboflavin + ATP = riboflavin-P (FMN) + ADP; FMN + ATP = riboflavin-ADP (FAD) + PP. Riboflavin is a water-soluble, yellow, fluorescent compound. The primary form of the vitamin is as an integral component of the coenzymes flavin mononucleotide (FMN) and flavin-adenine dinucleotide (FAD). It is in these bound coenzyme forms that riboflavin functions as a catalyst for redox reactions in numerous metabolic pathways and in energy production. ... The redox reactions in which flavocoenzymes participate include flavoprotein-catalyzed dehydrogenations that are both pyridine nucleotide (niacin) dependent and independent, reactions with sulfur-containing compounds, hydroxylations, oxidative decarboxylations (involving thiamin as its pyrophosphate), dioxygenations, and reduction of oxygen to hydrogen peroxide. There are obligatory roles of flavocoenzymes in the formation of some vitamins and their coenzymes. For example, the biosynthesis of two niacin-containing coenzymes from tryptophan occurs via FAD-dependent kynurenine hydroxylase, an FMN-dependent oxidase catalyzes the conversion of the 5'-phosphates of vitamin B6 to coenzymic pyridoxal 5'-phosphate, and an FAD-dependent dehydrogenase reduces 5,10-methylene-tetrahydrofolate to the 5'-methyl product that interfaces with the B12-dependent formation of methionine from homocysteine and thus with sulfur amino acid metabolism. For more Mechanism of Action (Complete) data for Riboflavin (7 total), please visit the HSDB record page.

Pharmacodynamics

Riboflavin or vitamin B2 is an easily absorbed, water-soluble micronutrient with a key role in maintaining human health. Like the other B vitamins, it supports energy production by aiding in the metabolising of fats, carbohydrates, and proteins. Vitamin B2 is also required for red blood cell formation and respiration, antibody production, and for regulating human growth and reproduction. It is essential for healthy skin, nails, hair growth and general good health, including regulating thyroid activity. Riboflavin also helps in the prevention or treatment of many types of eye disorders, including some cases of cataracts.

Mechanism of action

It is thought that the mechanism of action of thiamine on endothelial cells is related to a reduction in intracellular protein glycation by redirecting the glycolytic flux. Thiamine is mainly the transport form of the vitamin, while the active forms are phosphorylated thiamine derivatives. Natural derivatives of thiamine phosphate, such as thiamine monophosphate (ThMP), thiamine diphosphate (ThDP), also sometimes called thiamine pyrophosphate (TPP), thiamine triphosphate (ThTP), and thiamine triphosphate (AThTP), that act as coenzymes in addition to their each unique biological functions. Metabolic control analysis predicts that stimulators of transketolase enzyme synthesis such as thiamin (vitamin B-1) support a high rate of nucleic acid ribose synthesis necessary for tumor cell survival, chemotherapy resistance, and proliferation. Metabolic control analysis also predicts that transketolase inhibitor drugs will have the opposite effect on tumor cells. This may have important implications in the nutrition and future treatment of patients with cancer.

Pharmacodynamics

Thiamine is a vitamin with antioxidant, erythropoietic, cognition-and mood-modulatory, antiatherosclerotic, putative ergogenic, and detoxification activities. Thiamine has been found to protect against lead-induced lipid peroxidation in rat liver and kidney. Thiamine deficiency results in selective neuronal death in animal models. The neuronal death is associated with increased free radical production, suggesting that oxidative stress may play an important early role in brain damage associated with thiamine deficiency. Thiamine plays a key role in intracellular glucose metabolism and it is thought that thiamine inhibits the effect of glucose and insulin on arterial smooth muscle cell proliferation. Inhibition of endothelial cell proliferation may also promote atherosclerosis. Endothelial cells in culture have been found to have a decreased proliferative rate and delayed migration in response to hyperglycemic conditions. Thiamine has been shown to inhibit this effect of glucose on endothelial cells.

Mechanism of action

Choline is a major part of the polar head group of phosphatidylcholine. Phosphatidylcholine's role in the maintenance of cell membrane integrity is vital to all of the basic biological processes: information flow, intracellular communication and bioenergetics. Inadequate choline intake would negatively affect all these processes. Choline is also a major part of another membrane phospholipid, sphingomyelin, also important for the maintenance of cell structure and function. It is noteworthy and not surprising that choline deficiency in cell culture causes apoptosis or programmed cell death. This appears to be due to abnormalities in cell membrane phosphatidylcholine content and an increase in ceramide, a precursor, as well as a metabolite, of sphingomyelin. Ceramide accumulation, which is caused by choline deficiency, appears to activate Caspase, a type of enzyme that mediates apoptosis. Betaine or trimethylglycine is derived from choline via an oxidation reaction. Betaine is one of the factors that maintains low levels of homocysteine by resynthesizing L-methionine from homocysteine. Elevated homocysteine levels are a significant risk factor for atherosclerosis, as well as other cardiovascular and neurological disorders. Acetylcholine is one of the major neurotransmitters and requires choline for its synthesis. Adequate acetylcholine levels in the brain are believed to be protective against certain types of dementia, including Alzheimer's disease.

Pharmacodynamics

This compound is needed for good nerve conduction throughout the CNS (central nervous system) as it is a precursor to acetylcholine (ACh). Choline is also needed for gallbladder regulation, liver function and lecithin (a key lipid) formation. Choline also aids in fat and cholesterol metabolism and prevents excessive fat build up in the liver. Choline has been used to mitigate the effects of Parkinsonism and tardive dyskinesia. Choline deficiencies may result in excessive build-up of fat in the liver, high blood pressure, gastric ulcers, kidney and liver dysfunction and stunted growth.

Mechanism of action

Folic acid, as it is biochemically inactive, is converted to tetrahydrofolic acid and methyltetrahydrofolate by dihydrofolate reductase (DHFR). These folic acid congeners are transported across cells by receptor-mediated endocytosis where they are needed to maintain normal erythropoiesis, synthesize purine and thymidylate nucleic acids, interconvert amino acids, methylate tRNA, and generate and use formate. Using vitamin B12 as a cofactor, folic acid can normalize high homocysteine levels by remethylation of homocysteine to methionine via methionine synthetase. Folic acid, after conversion to tetrahydrofolic acid, is necessary for normal erythropoiesis, synthesis of purine and thymidylates, metabolism of amino acids such as glycine and methionine, and the metabolism of histidine. The principal biochemical function of folates is the mediation of one-carbon transfer reactions. 5-Methyltetrahydrofolate donates a methyl group to homocystine, in the conversion of homocystine to L-methionine. ... 5,10-Methyltetrahydrofolate is regenerated from tetrahydrofolate via the enzyme serine hydroxymethyltransferase, a reaction, which in addition to producing 5,10-methyltetrahydrofolate, yields glycine. ... 5,10-methyltetrahydrofolate, supplies the one carbon group for the methylation of deoxyuridylic acid to form the DNA precursor thymidylic acid. This reaction is catalyzed by thymidylate synthase and the folate product of the reaction is dihydrofolate. Dihydrofolate is converted to tetrahydrofolate via the enzyme dihydrofolate reductase ...

Pharmacodynamics

Folic acid is a water-soluble B-complex vitamin found in foods such as liver, kidney, yeast, and leafy, green vegetables. Also known as folate or Vitamin B9, folic acid is an essential cofactor for enzymes involved in DNA and RNA synthesis. More specifically, folic acid is required by the body for the synthesis of purines, pyrimidines, and methionine before incorporation into DNA or protein. Folic acid is the precursor of tetrahydrofolic acid, which is involved as a cofactor for transformylation reactions in the biosynthesis of purines and thymidylates of nucleic acids. Impairment of thymidylate synthesis in patients with folic acid deficiency is thought to account for the defective deoxyribonucleic acid (DNA) synthesis that leads to megaloblast formation and megaloblastic and macrocytic anemias. Folic acid is particularly important during phases of rapid cell division, such as infancy, pregnancy, and erythropoiesis, and plays a protective factor in the development of cancer. As humans are unable to synthesize folic acid endogenously, diet and supplementation is necessary to prevent deficiencies. In order to function properly within the body, folic acid must first be reduced by the enzyme dihydrofolate reductase (DHFR) into the cofactors dihydrofolate (DHF) and tetrahydrofolate (THF). This important pathway, which is required for de novo synthesis of nucleic acids and amino acids, is disrupted by anti-metabolite therapies such as [DB00563] as they function as DHFR inhibitors to prevent DNA synthesis in rapidly dividing cells, and therefore prevent the formation of DHF and THF. In general, folate serum levels below 5 ng/mL indicate folate deficiency, and levels below 2 ng/mL usually result in megaloblastic anemia.

Mechanism of action

Vitamin B6 is the collective term for a group of three related compounds, pyridoxine (PN), pyridoxal (PL) and pyridoxamine (PM), and their phosphorylated derivatives, pyridoxine 5'-phosphate (PNP), pyridoxal 5'-phosphate (PLP) and pyridoxamine 5'-phosphate (PMP). Although all six of these compounds should technically be referred to as vitamin B6, the term vitamin B6 is commonly used interchangeably with just one of them, pyridoxine. Vitamin B6, principally in its biologically active coenzyme form pyridoxal 5'-phosphate, is involved in a wide range of biochemical reactions, including the metabolism of amino acids and glycogen, the synthesis of nucleic acids, hemogloblin, sphingomyelin and other sphingolipids, and the synthesis of the neurotransmitters serotonin, dopamine, norepinephrine and gamma-aminobutyric acid (GABA).

Pharmacodynamics

Vitamin B6 (pyridoxine) is a water-soluble vitamin used in the prophylaxis and treatment of vitamin B6 deficiency and peripheral neuropathy in those receiving isoniazid (isonicotinic acid hydrazide, INH). Vitamin B6 has been found to lower systolic and diastolic blood pressure in a small group of subjects with essential hypertension. Hypertension is another risk factor for atherosclerosis and coronary heart disease. Another study showed pyridoxine hydrochloride to inhibit ADP- or epinephrine-induced platelet aggregation and to lower total cholesterol levels and increase HDL-cholesterol levels, again in a small group of subjects. Vitamin B6, in the form of pyridoxal 5'-phosphate, was found to protect vascular endothelial cells in culture from injury by activated platelets. Endothelial injury and dysfunction are critical initiating events in the pathogenesis of atherosclerosis. Human studies have demonstrated that vitamin B6 deficiency affects cellular and humoral responses of the immune system. Vitamin B6 deficiency results in altered lymphocyte differentiation and maturation, reduced delayed-type hypersensitivity (DTH) responses, impaired antibody production, decreased lymphocyte proliferation and decreased interleukin (IL)-2 production, among other immunologic activities.