PETDOG CONDITIONING PLUS TABLETS

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

• 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

Indications

• Nutritional supplementation
• Support for energy metabolism
• Support for immune function
• Management of stress and fatigue
• Support for skin health

Dosage

Children: Refer to product-specific dosing recommendations, as they can vary based on formulation and intended use.

Adults: Refer to product-specific dosing recommendations, as they can vary based on formulation and intended use.

Mechanism of action

Brewers yeast functions primarily as a source of B vitamins, which are essential for various metabolic processes in the body. It supports energy metabolism through the conversion of carbohydrates, fats, and proteins into energy. Additionally, the yeast contains chromium, which enhances insulin sensitivity and may aid in glucose metabolism.

Pharmacodynamics

The pharmacodynamics of brewers yeast are largely attributed to its nutritional content. The B vitamins, including thiamine, riboflavin, niacin, folate, and vitamin B12, contribute to the body's energy production and metabolic functions. The protein content provides essential amino acids that support tissue repair and muscle growth. The presence of beta-glucans may also contribute to immune system support.

Pharmacokinetics

Brewers yeast is typically ingested orally. Its components, primarily B vitamins, are absorbed in the gastrointestinal tract. The absorption rates can vary based on the individual's digestive health and the presence of other nutrients. Once absorbed, the vitamins are utilized by the body for various biochemical processes, while excess amounts are excreted through urine.

Pregnancy

Not enough reliable information is available on the safety of brewer's yeast during pregnancy. Consult a healthcare provider.

Breast-feeding

Brewer's yeast is generally considered safe during breastfeeding, but consult a healthcare provider before use.

Storage

Store in a cool, dry place, away from direct sunlight. Refrigeration may prolong freshness.

Formulations

• Powder
• Tablets
• Flakes
• Liquid extract

Indications

• Vitamin D deficiency
• Rickets
• Osteomalacia
• Osteoporosis
• Hypoparathyroidism

Dosage

Adults: The usual adult dose for vitamin D deficiency is 800 to 2000 IU daily, depending on the severity of deficiency and clinical condition. Higher doses may be used under medical supervision.

Mechanism of action

Cholecalciferol is converted to its active forms, 25-hydroxyvitamin D in the liver and 1,25-dihydroxyvitamin D in the kidneys. These metabolites enhance the intestinal absorption of calcium and phosphorus, increase serum calcium levels, and mobilize these minerals from bone. This process is regulated by parathyroid hormone, which influences calcium and phosphate metabolism, particularly in the kidneys.

Pharmacodynamics

The pharmacodynamics of cholecalciferol involve its conversion to active metabolites that play a significant role in calcium and phosphorus homeostasis. The metabolites facilitate intestinal absorption of these minerals, promote bone mineralization, and influence renal reabsorption. The onset of action occurs within 10 to 24 hours following administration, as metabolic activation is required for its biological effects.

Pharmacokinetics

Cholecalciferol is absorbed in the gastrointestinal tract, and its absorption is enhanced by the presence of dietary fats. It is transported in the bloodstream bound to vitamin D-binding protein. Once in the liver, it undergoes hydroxylation to form 25-hydroxyvitamin D, which is further converted in the kidneys to the active form, 1,25-dihydroxyvitamin D. The elimination half-life of cholecalciferol varies, typically spanning several days, and it is primarily excreted in bile and urine.

Adverse effects

• Hypercalcemia
• Hypercalciuria
• Nausea
• Vomiting
• Constipation
• Weakness
• Fatigue

Interactions

• May enhance the effects of thiazide diuretics, leading to increased risk of hypercalcemia
• Anticonvulsants may increase metabolism of vitamin D, leading to reduced effectiveness
• Cholestyramine may reduce absorption of vitamin D

Precautions

• Monitor serum calcium levels in patients with renal impairment
• Caution in patients with a history of hypercalcemia or hyperparathyroidism
• Use with caution in patients taking other medications that affect calcium metabolism

Pregnancy

Cholecalciferol can be used during pregnancy if indicated, as vitamin D is essential for fetal bone development.

Breast-feeding

Cholecalciferol is excreted in breast milk, but is generally considered safe during breastfeeding.

Storage

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

Formulations

• Capsules
• Tablets
• Liquid formulations

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.

Indications

• Nutritional supplementation
• Herbal therapy for various conditions
• Preservation of medicinal properties of plants

Dosage

Children: Dosage for dried herbal preparations in children should be approached cautiously and is best determined by a healthcare professional. Refer to paediatric guidelines for specific dosing recommendations.

Adults: Dosage for dried herbal preparations varies widely depending on the specific herb and its intended use. Refer to specific guidelines or reputable sources for dosing information.

Mechanism of action

The mechanism of action for dried herbal preparations varies depending on the specific plant material involved. Generally, the active constituents in dried herbs can exert their effects through various pathways, such as modulating neurotransmitter systems, influencing metabolic pathways, and acting on specific receptors in the body. For instance, flavonoids, terpenes, and alkaloids found in certain dried herbs can exhibit anti-inflammatory, antioxidant, or antimicrobial properties.

Pharmacodynamics

The pharmacodynamics of dried drugs depend on their specific chemical constituents. These compounds can affect physiological functions, such as modulating inflammatory responses, enhancing immune function, or affecting neurotransmission. The effects can vary widely based on the type of herb, the method of drying, and the concentration of active ingredients.

Pharmacokinetics

The pharmacokinetics of dried herbal preparations can vary significantly based on the specific herb used. Generally, after ingestion, the active compounds are absorbed in the gastrointestinal tract, metabolized primarily by the liver, and then excreted through urine or feces. The bioavailability of these compounds can be influenced by factors such as the form of the preparation (e.g., powder, extract), the presence of other food substances, and individual patient characteristics.

Pregnancy

Safety during pregnancy has not been established. Consult a healthcare provider before use.

Breast-feeding

Consult a healthcare provider before use during breastfeeding.

Storage

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

Indications

• Folate deficiency
• Megaloblastic anemia
• Prevention of neural tube defects in pregnancy
• Supplementation in patients on certain medications (e.g., methotrexate)

Dosage

Children: Refer to the BNF for Children for appropriate pa

Adults: Refer to specific guidelines or the BNF for appropriate adult dosing based on the indication.

Mechanism of action

Folate functions as a coenzyme in the conversion of homocysteine to methionine, a process that is vital for DNA synthesis and repair. It is involved in the one-carbon metabolism pathway, where it acts as a carrier of one-carbon units necessary for the synthesis of purines and thymidylate, thus supporting the production of nucleotides and DNA. This mechanism is particularly important in rapidly dividing cells.

Pharmacodynamics

Folate is critical for the formation of red blood cells and the proper functioning of the nervous system. It aids in the production of nucleic acids, which are essential for cell proliferation. Folate deficiency can lead to impaired DNA synthesis, resulting in megaloblastic anemia characterized by the presence of large, immature red blood cells in the bloodstream. Adequate folate levels are also associated with reduced risk of neural tube defects in developing fetuses.

Pharmacokinetics

Folate is absorbed in the proximal part of the small intestine, primarily in the jejunum, and is transported in the bloodstream bound to plasma proteins. It undergoes hepatic metabolism and is stored mainly in the liver. The elimination half-life varies, but dietary folate can be retained in the body for several weeks. Excess folate is excreted through the urine. The bioavailability of folate from food sources is lower compared to synthetic folic acid found in supplements.

Interactions

• folates+fluorouracil: Severe (increases risk of toxicity)
• folates+antiepileptics: Moderate (decreases concentration)
• folates+fosphenytoin: Moderate (decreases concentration)
• folates+phenobarbital: Moderate (decreases concentration)
• folates+phenytoin: Moderate (decreases concentration)
• folates+primidone: Moderate (decreases concentration)
• sulfasalazine+folates: Unknown (decreases absorption)

Pregnancy

Folate is essential for fetal development and is often recommended to prevent neural tube defects.

Breast-feeding

Folate is generally safe during breastfeeding, as it is important for both maternal and infant health.

Storage

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

Formulations

• Tablets
• Injection

Indications

• Oxidative stress-related conditions
• Inflammatory conditions
• Potential anti-aging applications
• Vascular health enhancement

Dosage

Children: Refer to specific product formulations and guidelines, as dosing can vary based on the concentration of hydrogen in the product used.

Adults: Refer to specific product formulations and guidelines, as dosing can vary based on the concentration of hydrogen in the product used.

Mechanism of action

Molecular hydrogen acts primarily as an antioxidant and anti-inflammatory agent. It is believed to exert its beneficial effects through the activation of the Nrf2 pathway, which enhances the expression of antioxidant enzymes and protects cells from oxidative stress. Hydrogen-rich environments have been shown to mitigate the harmful effects of various toxins on human umbilical vein endothelial cells, thereby promoting vascular health and longevity.

Pharmacodynamics

Hydrogen's pharmacodynamic properties are linked to its role as a potent antioxidant, which reduces reactive oxygen species (ROS) and modulates inflammation. It has been documented to counteract cellular senescence in endothelial cells, thereby maintaining vascular integrity and promoting overall health. The long-lasting effects of hydrogen exposure can be observed even after its concentration in the medium has decreased, suggesting a sustained activation of protective cellular pathways.

Pharmacokinetics

Hydrogen is a gaseous molecule that diffuses rapidly across biological membranes. Its absorption and distribution in the body are influenced by the method of administration, with hydrogen-rich water being a common delivery form. Once in the bloodstream, hydrogen is quickly utilized by tissues, and its concentration diminishes rapidly, with a half-life that can vary based on conditions. The elimination of hydrogen primarily occurs via exhalation, making it a non-toxic molecule with a favorable safety profile.

Pregnancy

Hydrogen is generally considered safe during pregnancy, but it is advisable to consult a healthcare provider for specific recommendations.

Breast-feeding

Hydrogen is considered safe during breastfeeding, but as with any substance, it is recommended to discuss with a healthcare provider.

Storage

Hydrogen should be stored in a cool, dry place away from direct sunlight and heat sources, in appropriate gas cylinders designed for compressed gases.

Formulations

• Hydrogen gas (H2)
• Hydrogen-rich water

Mechanism of action

Hydrogenphosphate acts as a substrate for various enzymatic reactions where phosphate groups are transferred or incorporated into organic molecules. It is involved in metabolic pathways such as nicotine biosynthesis and NAD/NADH cycling, facilitating biochemical reactions that are vital for cellular function.

Pharmacodynamics

Hydrogenphosphate is crucial for maintaining cellular homeostasis. It regulates acid-base balance and is involved in energy metabolism. The phosphate groups it provides are integral to the structure and function of ATP, which is the primary energy currency of the cell. Additionally, hydrogenphosphate influences signal transduction pathways through phosphorylation and dephosphorylation processes.

Pharmacokinetics

Hydrogenphosphate is readily absorbed in the gastrointestinal tract and distributed throughout the body. Its elimination primarily occurs through renal excretion, where it is filtered and reabsorbed by the kidneys. The balance of hydrogenphosphate levels is tightly regulated by various physiological mechanisms to ensure proper metabolic function.

Pregnancy

There is limited information regarding the safety of hydrogenphosphate in pregnancy. Consult relevant guidelines and consider potential risks versus benefits.

Breast-feeding

Data on the excretion of hydrogenphosphate in human milk are not available. Caution is advised.

Storage

Store in a cool, dry place away from direct sunlight. Ensure containers are tightly closed.

Indications

• Manganese deficiency
• Bone health and development
• Antioxidant support
• Enzyme cofactor in metabolic processes

Dosage

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

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

Mechanism of action

Manganese serves as a cofactor for several enzymes, including manganese superoxide dismutase (MnSOD), which protects cells from oxidative stress by catalyzing the dismutation of superoxide radicals into oxygen and hydrogen peroxide. It also participates in the activation of enzymes involved in carbohydrate, fat, and protein metabolism.

Pharmacodynamics

Manganese plays a role in various biochemical pathways, particularly in the metabolism of amino acids, cholesterol, glucose, and carbohydrates. It is crucial for bone formation and the maintenance of cartilage. Manganese also aids in the synthesis of glycosyltransferases, which are important for the formation of glycoproteins and proteoglycans.

Pharmacokinetics

Manganese is absorbed primarily in the small intestine, with absorption efficiency influenced by dietary factors and the presence of competing minerals. It is transported in the bloodstream bound to proteins such as alpha-2-macroglobulin and transferrin. Manganese is stored in the liver, pancreas, and bones, and is excreted primarily through bile and to a lesser extent in urine. Its half-life in the human body is not well defined due to its trace nature and variable absorption.

Pregnancy

Manganese is classified as a dietary mineral that is essential for human health, but excessive intake should be avoided during pregnancy as it may affect fetal development.

Breast-feeding

Manganese is present in breast milk, and normal dietary intake is considered safe during breastfeeding. However, excessive supplementation should be avoided.

Storage

Store in a cool, dry place, away from direct light and moisture.

Indications

• Dermatitis
• Acne
• Rosacea
• Hyperpigmentation
• Skin aging

Dosage

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

Adults: Refer to the BNF for specific dosing guidelines based on the condition being treated.

Mechanism of action

Niacinamide functions primarily as a precursor to NAD and NADP, which are crucial for numerous enzymatic reactions in the body. It is involved in the NAD salvage pathway, which recycles nicotinamide for NAD synthesis. This process is vital for cellular energy production and metabolic processes. Niacinamide also has anti-inflammatory properties, which may contribute to its effects in skin health.

Pharmacodynamics

Niacinamide exhibits various pharmacological effects, including enhancing skin barrier function, reducing inflammation, and improving skin pigmentation. It has been shown to modulate keratinocyte function, improve collagen synthesis, and decrease the synthesis of sebum, thereby providing beneficial effects in conditions like acne and rosacea.

Pharmacokinetics

Niacinamide is readily absorbed from the gastrointestinal tract. It is distributed widely throughout the body and can cross biological membranes. The metabolism of niacinamide primarily occurs in the liver through methylation and conjugation, and it is excreted in urine as metabolites. The half-life of niacinamide is approximately 1-2 hours, and its effects can be prolonged due to its role in NAD synthesis.

Pregnancy

No evidence of harm, but use only if clearly needed.

Breast-feeding

Considered safe to use while breastfeeding.

Storage

Store in a cool, dry place away from light.

Formulations

• {'type': 'Topical cream', 'concentration': 'Various concentrations available'}
• {'type': 'Oral tablets', 'concentration': '100 mg, 250 mg, 500 mg'}

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

• Vitamin A deficiency
• Night blindness
• Impaired wound healing
• Epithelial disorders

Dosage

Children: Refer to BNF for Children for specific paediatric dosing information.

Adults: Refer to BNF for specific adult dosing information.

Mechanism of action

Retinol is converted in the retina to 11-cis-retinal, which is crucial for the conversion of light into neural signals necessary for vision. It binds to opsin in rhodopsin, facilitating the isomerization to all-trans-retinal upon exposure to light, thus triggering visual signaling. Additionally, retinol interacts with retinoic acid receptors (RARs) and retinoid-X receptors (RXRs) as transcription factors, modulating gene expression related to cellular differentiation and growth.

Pharmacodynamics

Vitamin A is effective in treating Vitamin A deficiency, which can lead to vision impairment and other health issues. It plays a critical role in various biological processes including vision, cellular differentiation, reproduction, and immune system function. Its deficiency can cause symptoms such as night blindness and impaired wound healing, while adequate levels support growth and development.

Pharmacokinetics

Retinol is absorbed from the gastrointestinal tract and stored in the liver, where it can be mobilized as needed. It undergoes metabolism primarily in the liver, where it is converted to retinal and retinoic acid, the active forms of Vitamin A. The elimination half-life varies, but retinol is generally excreted in urine and bile. The bioavailability can be affected by dietary fat intake.

Adverse effects

• Nausea
• Vomiting
• Headache
• Dizziness
• Fatigue
• Irritability
• Dry skin
• Peeling of skin
• Itching
• Blurred vision

Precautions

• Use with caution in patients with liver disease due to potential hepatotoxicity.
• Monitor for signs of vitamin A toxicity, especially in patients on high doses or prolonged therapy.
• Caution in patients with a history of alcohol abuse, as it may exacerbate liver conditions.

Pregnancy

Retinol should be used with caution during pregnancy due to the risk of teratogenic effects. High doses of vitamin A can lead to fetal malformations.

Breast-feeding

Retinol is generally considered safe during breastfeeding, but excessive intake should be avoided to prevent potential adverse effects on the infant.

Storage

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

Formulations

• Capsules
• Tablets
• Oral solutions
• Topical preparations

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

Indications

• Prevention of vitamin E deficiency
• Antioxidant therapy
• Support in conditions related to oxidative stress

Dosage

Children: Refer to BNF for Children for specific dosage guidelines.

Adults: Refer to BNF for specific dosage guidelines.

Mechanism of action

Tocopherol acts as a radical scavenger, primarily functioning as an antioxidant for lipid bilayers. It donates hydrogen atoms to free radicals, trapping them and preventing cellular damage. Its effectiveness is influenced by its location within the membrane and its interaction with cytosolic reductants like ascorbate. Tocopherol can trap multiple radicals, including alkyl and peroxy radicals.

Pharmacodynamics

The antioxidant properties of tocopherol lead to significant pharmacodynamic effects, including the inhibition of cell death through modulation of protein kinase C (PKC). Tocopherol also exhibits anti-inflammatory effects, which can be attributed to its influence on cytokines, prostaglandins, prostanoids, and thromboxanes. These interactions may contribute to its protective effects in various pathological conditions.

Pharmacokinetics

Tocopherol is absorbed in the intestines and its bioavailability can be influenced by dietary fat intake. It is transported in the plasma primarily bound to lipoproteins. Tocopherol is stored in adipose tissue and the liver, and its elimination occurs through bile and urine. The half-life of tocopherol can vary depending on the individual's nutritional status and other factors.

Pregnancy

Tocopherol is generally considered safe during pregnancy, but it is advisable to consult a healthcare provider before use.

Breast-feeding

Tocopherol is excreted in breast milk, and while it is considered safe, a healthcare provider should be consulted for specific recommendations.

Storage

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

Indications

• Nutritional supplement
• Support for digestive health
• Enhancement of immune function
• Source of B vitamins

Dosage

Children: Refer to specific product guidelines, as dosage may vary based on formulation and intended use.

Adults: Refer to specific product guidelines, as dosage may vary based on formulation and intended use.

Mechanism of action

Yeast operates through various biochemical pathways, primarily by fermenting sugars to produce alcohol and carbon dioxide. In its role as a dietary supplement, it may enhance gut health by supporting the growth of beneficial gut flora and improving nutrient absorption. Additionally, yeast extract can modulate immune responses and has been studied for its potential antioxidant properties.

Pharmacodynamics

Yeast contains various bioactive compounds, including beta-glucans, which may enhance immune function and exhibit anti-inflammatory properties. The nutrients in yeast, such as B vitamins and amino acids, play crucial roles in metabolic processes, energy production, and overall health maintenance. The fermentation products can also influence gut microbiota composition and enhance digestive health.

Pharmacokinetics

When ingested, yeast components are digested in the gastrointestinal tract where they are broken down into absorbable nutrients. The bioavailability of vitamins and minerals from yeast can vary based on the preparation method. The metabolic byproducts of yeast fermentation are utilized by the body for energy and other metabolic functions. The elimination of yeast components occurs primarily through fecal excretion, as well as through metabolic pathways in the liver.

Adverse effects

• Gastrointestinal discomfort
• Gas and bloating
• Allergic reactions
• Headache

Precautions

• Use with caution in individuals with a compromised immune system
• May cause allergic reactions in sensitive individuals

Pregnancy

Generally considered safe, but consult a healthcare provider before use.

Breast-feeding

Generally considered safe, but consult a healthcare provider before use.

Storage

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

Formulations

• Capsules
• Tablets
• Powder
• Liquid

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

Most individuals naturally generate adequate amounts of vitamin D through ordinary dietary intake of vitamin D (in some foods like eggs, fish, and cheese) and natural photochemical conversion of the vitamin D3 precursor 7-dehydrocholesterol in the skin via exposure to sunlight. Conversely, vitamin D deficiency can often occur from a combination of insufficient exposure to sunlight, inadequate dietary intake of vitamin D, genetic defects with endogenous vitamin D receptor, or even severe liver or kidney disease. Such deficiency is known for resulting in conditions like rickets or osteomalacia, all of which reflect inadequate mineralization of bone, enhanced compensatory skeletal demineralization, resultant decreased calcium ion blood concentrations, and increases in the production and secretion of parathyroid hormone. Increases in parathyroid hormone stimulate the mobilization of skeletal calcium and the renal excretion of phosphorus. This enhanced mobilization of skeletal calcium leads towards porotic bone conditions. Ordinarily, while vitamin D3 is made naturally via photochemical processes in the skin, both itself and vitamin D2 can be found in various food and pharmaceutical sources as dietary supplements. The principal biological function of vitamin D is the maintenance of normal levels of serum calcium and phosphorus in the bloodstream by enhancing the efficacy of the small intestine to absorb these minerals from the diet. At the liver, vitamin D3 or D2 is hydroxylated to 25-hydroxyvitamin D and then finally to the primary active metabolite 1,25-dihydroxyvitamin D in the kidney via further hydroxylation. This final metabolite binds to endogenous vitamin d receptors, which results in a variety of regulatory roles - including maintaining calcium balance, the regulation of parathyroid hormone, the promotion of the renal reabsorption of calcium, increased intestinal absorption of calcium and phosphorus, and increased calcium and phosphorus mobilization of calcium and phosphorus from bone to plasma to maintain balanced levels of each in bone and the plasma. In particular, calcitriol interacts with vitamin D receptors in the small intestine to enhance the efficiency of intestinal calcium and phosphorous absorption from about 10-15% to 30-40% and 60% increased to 80%, respectively. Furthermore, calcitriol binds with vitamin D receptors in osteoblasts to stimulate a receptor activator of nuclear factor kB ligand (or RANKL) which subsequently interacts with receptor activator of nuclear factor kB (NFkB) on immature preosteoclasts, causing them to become mature bone-resorbing osteoclasts. Such mature osteoclasts ultimately function in removing calcium and phosphorus from bone to maintain blood calcium and phosphorus levels. Moreover, calcitriol also stimulates calcium reabsorption from the glomerular filtrate in the kidneys. Additionally, it is believed that when calcitriol binds with nuclear vitamin D receptors, that this bound complex itself binds to retinoic acid X receptor (RXR) to generate a heterodimeric complex that consequently binds to specific nucleotide sequences in the DNA called vitamin D response elements. When bound, various transcription factors attach to this complex, resulting in either up or down-regulation of the associated gene's activity. It is thought that there may be as much as 200 to 2000 genes that possess vitamin D response elements or that are influenced indirectly to control a multitude of genes across the genome. It is in this way that cholecalciferol is believed to function in regulating gene transcription associated with cancer risk, autoimmune disorders, and cardiovascular disease linked to vitamin D deficiency. In fact, there has been some research to suggest calcitriol may also be able to prevent malignancies by inducing cellular maturation and inducing apoptosis and inhibiting angiogenesis, exhibit anti-inflammatory effects by inhibiting foam cell formation and promoting angiogenesis in en

Pharmacodynamics

The in vivo synthesis of the predominant two biologically active metabolites of vitamin D occurs in two steps. The first hydroxylation of vitamin D3 cholecalciferol (or D2) occurs in the liver to yield 25-hydroxyvitamin D while the second hydroxylation happens in the kidneys to give 1, 25-dihydroxyvitamin D. These vitamin D metabolites subsequently facilitate the active absorption of calcium and phosphorus in the small intestine, serving to increase serum calcium and phosphate levels sufficiently to allow bone mineralization. Conversely, these vitamin D metabolites also assist in mobilizing calcium and phosphate from bone and likely increase the reabsorption of calcium and perhaps also of phosphate via the renal tubules. There exists a period of 10 to 24 hours between the administration of cholecalciferol and the initiation of its action in the body due to the necessity of synthesis of the active vitamin D metabolites in the liver and kidneys. It is parathyroid hormone that is responsible for the regulation of such metabolism at the level of the kidneys.

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

Substantial evidence indicates that molecular hydrogen (H2) has beneficial vascular effects because of its antioxidant and/or anti-inflammatory effects. Thus, hydrogen-rich water may prove to be an effective anti-aging drink. This study examined the effects of H2 on endothelial senescence and clarified the mechanisms involved. Hydrogen-rich medium was produced by a high-purity hydrogen gas generator. Human umbilical vein endothelial cells (HUVECs) were incubated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for various time periods in normal or hydrogen-rich medium. The baseline H2concentration in hydrogen-rich medium was 0.55 +/- 0.07 mmol/L. This concentration gradually decreased, and H2 was almost undetectable in medium after 12 hr. At 24 hr after TCDD exposure, HUVECs treated with TCDD exhibited increased 8OHdG and acetyl-p53 expression, decreased nicotinamide adenine dinucleotide (NAD(+))/NADH ratio, impaired Sirt1 activity, and enhanced senescence-associated beta-galactosidase. However, HUVECs incubated in hydrogen-rich medium did not exhibit these TCDD-induced changes accompanying Nrf2 activation, which was observed even after H2 was undetectable in the medium. Chrysin, an inhibitor of Nrf2, abolished the protective effects of H2 on HUVECs. H2 has long-lasting antioxidant and anti-aging effects on vascular endothelial cells through the Nrf2 pathway, even after transient exposure to H2. Hydrogen-rich water may thus be a functional drink that increases longevity. /Hydrogen-rich water/ Amyloid beta (Abeta) peptides are identified /as a/ cause of neurodegenerative diseases such as Alzheimer's disease (AD). Previous evidence suggests Abeta-induced neurotoxicity is linked to the stimulation of reactive oxygen species (ROS) production. The accumulation of Abeta-induced ROS leads to increased mitochondrial dysfunction and triggers apoptotic cell death. This suggests antioxidant therapies may be beneficial for preventing ROS-related diseases such as AD. Recently, hydrogen-rich water (HRW) has been proven effective in treating oxidative stress-induced disorders because of its ROS-scavenging abilities. However, the precise molecular mechanisms whereby HRW prevents neuronal death are still unclear. In the present study, we evaluated the putative pathways by which HRW protects against Abeta-induced cytotoxicity /in SK-N-MC cells/. Our results indicated that HRW directly counteracts oxidative damage by neutralizing excessive ROS, leading to the alleviation of Abeta-induced cell death. In addition, HRW also stimulated AMP-activated protein kinase (AMPK) in a sirtuin 1 (Sirt1)-dependent pathway, which upregulates forkhead box protein O3a (FoxO3a) downstream antioxidant response and diminishes Abeta-induced mitochondrial potential loss and oxidative stress. Taken together, our findings suggest that HRW may have potential therapeutic value to inhibit Abeta-induced neurotoxicity. /Hydrogen-rich water/ The NLRP3 inflammasome, an intracellular multi-protein complex controlling the maturation of cytokine interleukin-1beta, plays an important role in lipopolysaccharide (LPS)-induced inflammatory cascades. Recently, the production of mitochondrial reactive oxygen species (mtROS) in macrophages stimulated with LPS has been suggested to act as a trigger during the process of NLRP3 inflammasome activation that can be blocked by some mitochondria-targeted antioxidants. Known as a ROS scavenger, molecular hydrogen (H2) has been shown to possess therapeutic benefit on LPS-induced inflammatory damage in many animal experiments. Due to the unique molecular structure, H2 can easily target the mitochondria, suggesting that H2 is a potential antagonist of mtROS-dependent NLRP3 inflammasome activation. Here we have showed that, in mouse macrophages, H2 exhibited substantial inhibitory activity against LPS-initiated NLRP3 inflammasome activation by scavenging mtROS. Moreover, the elimination of mtROS by H2 resultantly inhibited mtROS-mediated NLRP3 deubi

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.

Mechanism of action

Vision:Vitamin A (all-<i>trans</i> retinol) is converted in the retina to the 11-<i>cis</i>-isomer of retinaldehyde or 11-<i>cis</i>-retinal. 11-<i>cis</i>-retinal functions in the retina in the transduction of light into the neural signals necessary for vision. 11-<i>cis</i>-retinal, while attached to opsin in rhodopsin is isomerized to all-<i>trans</i>-retinal by light. This is the event that triggers the nerve impulse to the brain which allows for the perception of light. All-<i>trans</i>-retinal is then released from opsin and reduced to all-<i>trans</i>-retinol. All-<i>trans</i>-retinol is isomerized to 11-<i>cis</i>-retinol in the dark, and then oxidized to 11-<i>cis</i>-retinal. 11-<i>cis</i>-retinal recombines with opsin to re-form rhodopsin. Night blindness or defective vision at low illumination results from a failure to re-synthesize 11-<i>cis</i> retinal rapidly. Epithelial differentiation: The role of Vitamin A in epithelial differentiation, as well as in other physiological processes, involves the binding of Vitamin A to two families of nuclear retinoid receptors (retinoic acid receptors, RARs; and retinoid-X receptors, RXRs). These receptors function as ligand-activated transcription factors that modulate gene transcription. When there is not enough Vitamin A to bind these receptors, natural cell differentiation and growth are interrupted. Topical vitamin A can reverse the impairment of wound healing seen in patients receiving corticosteroids, perhaps by restoring the normal inflammatory reaction in the wound. The possibility has been suggested that systemic vitamin A could inhibit the anti-inflammatory effect of systemic corticosteroids. Retinol arrested proliferation of cultured neuroblastoma cells at concentrations of 50 um. A correlation existed between inhibition of growth and inhibition of ornithine decarboxylase in both neuroblastoma cells and glioma cells with retinol. In rats exptl-hypervitaminosis A has been shown ... to produce severe damage of the retina, mainly in the pigment epithelium according to electron microscopy. Alcohol dehydrogenase activity was shown to disappear in the pigment epithelium and visual cells ... . /The authors/ have shown that in an experimental cell culture system consisting of carcinogen-treated 10T1/2 cells, both retinoids and all dietary carotenoids examined can reversibly inhibit neoplastic transformation in the post-initiation phase of carcinogenesis. This activity strongly correlates with their ability to increase gap junctional intercellular communication by up-regulating the expression of the gene CX43 (connexin43). Connexins comprise the structural unit of gap junctions, organelles which allow direct transfer of signals, nutrients and waste products between contacting cells. CX43 is the most widely expressed member of the gap junction family of genes, and we have demonstrated that its expression is strongly down-regulated in human cancers and in several premalignant conditions. When several human tumour cell lines were genetically engineered to conditionally express CX43 under the influence of a tetracycline promoter, their neoplastic phenotype was strongly attenuated. Specifically, induced cells were inhibited from growing in an anchorage-independent manner and, additionally, growth as xenografts in immunocompromised animals was also strongly attenuated. Growth inhibition in suspension was associated both with increased G(1) cell-cycle arrest and with increased apoptosis. /The authors/ propose a model whereby junctional communication allows the transfer of growth inhibitory signals from normal to neoplastic cells and that retinoids and carotenoids, by increasing signal transfer, act to prevent cancer.

Pharmacodynamics

Vitamin A is effective for the treatment of Vitamin A deficiency. Vitamin A refers to a group of fat-soluble substances that are structurally related to and possess the biological activity of the parent substance of the group called all-<i>trans</i> retinol or retinol. Vitamin A plays vital roles in vision, epithelial differentiation, growth, reproduction, pattern formation during embryogenesis, bone development, hematopoiesis and brain development. It is also important for the maintenance of the proper functioning of the immune system.

Mechanism of action

Tocopherol acts as a radical scavenger. It mainly acts as an antioxidant for lipid bilayers. Tocopherol's functions depend on the H-atom donating ability, location, and movement within the membrane, as well as the efficiency in the radical recycling by some cytosolic reductants such as ascorbate. Tocopherol actions are related to the trap of radicals, and it has been shown that even in the absence of substituents in the ortho-positions, tocopherol can trap more than two radicals. The type of radicals available for tocopherol are alkyl and peroxy.

Pharmacodynamics

The antioxidant effects of tocopherol can be translated into different changes at the pharmacodynamic level. In vitro studies have shown that this antioxidant activity can produce modification in protein kinase C (PKC) which will later be translated into an inhibition of cell death. Some other derivate effects are the anti-inflammatory properties of tocopherol which can be related to the modulation of cytokines or prostaglandins, prostanoids and thromboxanes.