PRENATAL DHA SF TABLETS

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

• 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

• 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

• Iodine deficiency
• Goiter
• Hypothyroidism
• Thyroiditis
• Fibrocystic breast disease

Dosage

Children: Refer to the BNF for Children for appropriate dosing guidelines based on age and weight.

Adults: Refer to the BNF for appropriate dosing guidelines based on condition and clinical judgment.

Mechanism of action

Molecular iodine inhibits the induction and promotion of carcinogenesis in mammary tissues and has shown beneficial effects in fibrocystic breast disease. It temporarily decreases thyroid hormone production through the acute Wolff-Chaikoff effect, followed by a return to normal hormone synthesis due to down regulation of the sodium-iodide symport. This mechanism can lead to a transient hypothyroid state in some individuals with underlying thyroid conditions.

Pharmacodynamics

Iodine is vital for the synthesis of thyroid hormones thyroxine (T4) and triiodothyronine (T3). It affects the metabolism of amine-derived hormones and plays a role in amino acid metabolism. The acute excess of iodide can lead to decreased circulating levels of T4 and T3 in susceptible individuals, while most people can escape this effect and maintain normal thyroid function.

Pharmacokinetics

Iodine is absorbed primarily in the gastrointestinal tract and is distributed throughout the body, particularly in the thyroid gland, where it is concentrated for hormone synthesis. The kidney plays a significant role in the excretion of excess iodine. The half-life of iodine in the body varies and can be influenced by dietary intake and underlying health conditions.

Adverse effects

• Hypothyroidism
• Hyperthyroidism
• Iodine allergy
• Gastrointestinal disturbances

Interactions

• Thyroid hormones
• Antithyroid drugs
• Lithium
• Diuretics

Precautions

• Use with caution in patients with thyroid dysfunction
• Monitor thyroid function periodically during treatment
• Pregnant or breastfeeding women should consult a healthcare provider before use

Pregnancy

Iodine is essential for fetal thyroid hormone synthesis, but excessive iodine intake should be avoided.

Breast-feeding

Iodine is excreted in breast milk; consult a healthcare provider regarding supplementation.

Storage

Store in a cool, dry place away from light.

Formulations

• Iodine solution
• Iodine tincture
• Potassium iodide tablets

Indications

• Vitamin B3 deficiency
• Hyperlipidemia
• Dyslipidemia

Mechanism of action

Niacin decreases lipids and apolipoprotein B (apo B)-containing lipoproteins by modulating triglyceride synthesis in the liver and inhibiting lipolysis in adipose tissue. It inhibits hepatocyte diacylglycerol acyltransferase-2, preventing the final step of triglyceride synthesis, leading to reduced VLDL production. Additionally, niacin inhibits HDL catabolism receptors, increasing HDL levels and half-life. Acute effects include inhibition of nonesterified fatty acid release from adipocytes and stimulation of prostaglandin release from skin Langerhans cells, although these acute effects diminish over time.

Pharmacodynamics

Niacin is used therapeutically to treat vitamin deficiencies and to manage conditions like hyperlipidemia and dyslipidemia. It effectively reduces levels of VLDL and LDL while increasing HDL levels. Niacin has a wide therapeutic window, with typical oral doses ranging from 500 mg to 2000 mg. Caution is advised in patients with diabetes, renal failure, uncontrolled hypothyroidism, and in elderly patients, particularly when combined with simvastatin or lovastatin, due to an increased risk of myopathy and rhabdomyolysis.

Pharmacokinetics

Niacin is absorbed from the gastrointestinal tract and undergoes hepatic metabolism. It is excreted primarily in the urine. The pharmacokinetics can be affected by factors such as age, renal function, and concomitant medications. Peak plasma concentrations are typically reached within 30 minutes to 2 hours after oral administration, depending on the formulation used.

Contra-indications

• Hypersensitivity to niacin or any of its components
• Active liver disease
• Peptic ulcer disease

Adverse effects

• Flushing
• Itching
• Nausea
• Vomiting
• Diarrhea
• Abdominal pain
• Hepatotoxicity
• Hyperglycemia
• Gout exacerbation

Interactions

• Increased risk of myopathy and rhabdomyolysis with statins such as simvastatin or lovastatin
• May enhance the effects of antihypertensive medications
• Potential interaction with anticoagulants

Precautions

• Caution in patients with diabetes due to potential for hyperglycemia
• Monitor liver function tests periodically during prolonged therapy
• Use with caution in patients with renal impairment
• Elderly patients may be more susceptible to adverse effects

Pregnancy

Niacin should only be used during pregnancy if clearly needed and the benefits outweigh the risks. Consult with a healthcare provider for individual assessment.

Breast-feeding

Niacin is excreted in breast milk. Caution is advised when administering to nursing mothers, and a decision should be made whether to discontinue breastfeeding or the drug.

Storage

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

Formulations

• Immediate-release tablets
• Extended-release tablets
• Sustained-release tablets

Indications

• Cardiovascular disease prevention
• Hypertriglyceridemia
• Rheumatoid arthritis
• Inflammatory bowel disease
• Cognitive decline and dementia
• Mood disorders

Dosage

Adults: Dosage varies based on the condition being treated. For general health, a common recommendation is 250-500 mg of combined EPA and DHA

Mechanism of action

Omega fatty acids exert their effects through various mechanisms, including the modulation of inflammatory pathways and the synthesis of specialized pro-resolving mediators. They are incorporated into cell membranes, affecting membrane fluidity and receptor function. Omega-3 fatty acids can also decrease the production of pro-inflammatory eicosanoids and increase anti-inflammatory mediators, promoting a balanced inflammatory response.

Pharmacodynamics

The pharmacodynamics of omega fatty acids involve their role in cellular signaling, gene expression, and lipid metabolism. Omega-3 fatty acids, particularly EPA and DHA, have been shown to influence the resolution of inflammation and enhance endothelial function. They also play a role in neuroprotection and cognitive function, with evidence suggesting that adequate omega-3 intake is associated with reduced risk of neurodegenerative diseases.

Pharmacokinetics

Omega fatty acids are absorbed in the intestine through the action of bile salts and pancreatic enzymes. Once absorbed, they are transported via chylomicrons into the lymphatic system and then into the bloodstream. They are distributed throughout the body, particularly in the brain and heart. The half-life of omega fatty acids can vary, with some studies suggesting an elimination half-life of several days to weeks, depending on the specific fatty acid and individual metabolism. They undergo beta-oxidation for energy production and can be converted into eicosanoids, which mediate various physiological functions.

Adverse effects

• Nausea
• Diarrhea
• Fishy aftertaste
• Allergic reactions
• Increased bleeding risk

Interactions

• Anticoagulants may increase the risk of bleeding when combined with omega-3 fatty acids
• Antihypertensive medications may have additive effects on blood pressure

Precautions

• Use cautiously in patients with bleeding disorders
• Monitor patients on anticoagulants for signs of increased bleeding
• Consider the source of omega-3 fatty acids, as some may contain contaminants

Pregnancy

Generally considered safe when used in recommended amounts, but high doses should be avoided due to potential bleeding risk.

Breast-feeding

Considered safe; omega-3 fatty acids can be beneficial for both mother and infant.

Storage

Store in a cool, dry place, away from light. Refrigeration may be required for some formulations to maintain stability.

Formulations

• Capsules
• Softgels
• Liquid oil
• Fortified foods

Indications

• Pantothenic acid deficiency
• Adrenal insufficiency
• Hyperlipidemia
• Support for energy metabolism

Dosage

Children: Refer to specific guidelines or clinical resources for paediatric dosing recommendations.

Adults: Refer to specific guidelines or clinical resources for adult dosing recommendations.

Mechanism of action

Pantothenic acid is converted into coenzyme A in the body, which is vital for the metabolism of fatty acids and the synthesis of acetylcholine. CoA is involved in the acylation of proteins and the metabolism of carbohydrates and amino acids, facilitating the production of energy and the synthesis of lipids.

Pharmacodynamics

Pantothenic acid's pharmacodynamic effects are primarily related to its role as a precursor of coenzyme A. It aids in energy production through the oxidation of fatty acids and is essential for synthesizing steroid hormones in the adrenal glands. It may also play a role in the synthesis of neurotransmitters and hemoglobin.

Pharmacokinetics

Pantothenic acid is absorbed in the gastrointestinal tract and is widely distributed in body tissues. It is actively transported into cells and is not stored in significant amounts, necessitating regular dietary intake. The elimination occurs primarily through urine, where it is excreted as metabolites.

Pregnancy

Pantothenic acid is generally considered safe during pregnancy, as it is a water-soluble vitamin essential for various bodily functions. However, high doses should be avoided unless specifically recommended by a healthcare provider.

Breast-feeding

Pantothenic acid is also considered safe during breastfeeding, as it is a necessary nutrient for both the mother and the infant. Adequate intake is important for lactating women.

Storage

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

Indications

• Thiamine deficiency
• Wernicke's encephalopathy
• Korsakoff syndrome
• Beriberi
• Neuropathies associated with diabetes
• Supportive therapy in chronic alcoholism

Dosage

Children: For children, dosages vary based on

Adults: For adults, the usual oral dosage of thiamine for deficiency is 100 mg three times daily for up to 2 weeks, followed by a maintenance dose of 100 mg daily.

Mechanism of action

Thiamine's mechanism of action primarily involves the reduction of intracellular protein glycation by redirecting glycolytic flux. It acts as a coenzyme for transketolase, which is essential for the pentose phosphate pathway, thereby supporting nucleic acid and neurotransmitter synthesis. This action may also affect tumor cell metabolism and survival, indicating potential implications in cancer treatment.

Pharmacodynamics

Thiamine exhibits several pharmacodynamic effects, including antioxidant activity, modulation of erythropoiesis, and neuroprotection. It has been shown to mitigate oxidative stress, which is associated with neuronal damage in thiamine deficiency. Thiamine also influences arterial smooth muscle cell proliferation and endothelial cell function, potentially reducing the risk of atherosclerosis under hyperglycemic conditions.

Pharmacokinetics

Thiamine is absorbed in the small intestine and transported in the bloodstream predominantly as thiamine pyrophosphate. The body stores thiamine primarily in the liver, heart, and muscle tissues, and it is excreted via the kidneys. The half-life of thiamine is relatively short, necessitating regular dietary intake to maintain adequate levels. Its bioavailability can be affected by factors such as alcohol consumption and certain medical conditions.

Adverse effects

• Allergic reactions
• Skin rash
• Nausea
• Irritability

Precautions

• Monitor patients with renal impairment
• Use with caution in patients with thiamine hypersensitivity

Pregnancy

Thiamine is generally considered safe during pregnancy and is essential for fetal development.

Breast-feeding

Thiamine is excreted in breast milk and is important for infant development; supplementation may be beneficial.

Storage

Store in a tightly closed container, in a cool, dry place away from light.

Formulations

• Oral tablets
• Injectable forms

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

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

Molecular iodine is known to inhibit the induction and promotion of N-methyl-n-nitrosourea-induced mammary carcinogenesis, to regress 7,12-dimethylbenz(a)anthracene-induced breast tumors in rats.It has also been shown to have beneficial effects in fibrocystic human breast disease. An acute iodide excess (above the preexisting dietary intake) transiently decreases the production of thyroid hormones in the thyroid gland; this is referred to as the acute Wolff-Chaikoff effect. In normal people, this is followed by a return to normal levels of hormone synthesis, referred to as escape from the acute Wolff-Chaikoff effect, without a significant change in circulating hormone levels. Escape is thought to be the result of down regulation of the sodium-iodide symport (NIS), the iodide transporter in the thyroid gland, resulting in a decrease in the intrathyroidal iodine and the resumption of normal hormone synthesis. An acute or chronic excess of iodide can also decrease circulating T4 and T3 levels and induce a hypothyroid state in some people who have underlying thyroid disorders. These effects are the result of a failure to escape from the acute Wolff-Chaikoff effect. Most people who experience iodine-induced hypothyroidism recover when the excess iodine intake is discontinued.

Mechanism of action

Niacin performs a number of functions in the body and so has many mechanisms, not all of which have been fully described. Niacin can decrease lipids and apolipoprotein B (apo B)-containing lipoproteins by modulating triglyceride synthesis in the liver, which degrades apo B, or by modulating lipolysis in adipose tissue. Niacin inhibits hepatocyte diacylglycerol acyltransferase-2. This action prevents the final step of triglyceride synthesis in hepatocytes, limiting available triglycerides for very low density lipoproteins (VLDL). This activity also leads to intracellular degradation of apo B and decreased production of low density lipoproteins, the catabolic product of VLDL. Niacin also inhibits a high density lipoprotein (HDL) catabolism receptor, which increases the levels and half life of HDL. Prolonged niacin treatment elicits beneficial effects on the plasma lipid and lipoprotein profile that is associated with a protective CVD risk profile. Acute niacin treatment inhibits nonesterified fatty acid release from adipocytes and stimulates prostaglandin release from skin Langerhans cells, but the acute effects diminish upon prolonged treatment, while the beneficial effects remain. To gain insight in the prolonged effects of niacin on lipid metabolism in adipocytes, we used a mouse model with a human-like lipoprotein metabolism and drug response [female APOE*3-Leiden.CETP (apoE3 Leiden cholesteryl ester transfer protein) mice] treated with and without niacin for 15 weeks. The gene expression profile of gonadal white adipose tissue (gWAT) from niacin-treated mice showed an upregulation of the "biosynthesis of unsaturated fatty acids" pathway, which was corroborated by quantitative PCR and analysis of the FA ratios in gWAT. Also, adipocytes from niacin-treated mice secreted more of the PUFA DHA ex vivo. This resulted in an increased DHA/arachidonic acid (AA) ratio in the adipocyte FA secretion profile and in plasma of niacin-treated mice. Interestingly, the DHA metabolite 19,20-dihydroxy docosapentaenoic acid (19,20-diHDPA) was increased in plasma of niacin-treated mice. Both an increased DHA/AA ratio and increased 19,20-diHDPA are indicative for an anti-inflammatory profile and may indirectly contribute to the atheroprotective lipid and lipoprotein profile associated with prolonged niacin treatment. /The study objective was/ to determine the effects of niacin on adiponectin and markers of adipose tissue inflammation in a mouse model of obesity. Male C57BL/6 mice were placed on a control or high-fat diet (HFD) and were maintained on such diets for the duration of the study. After 6 weeks on the control or high fat diets, vehicle or niacin treatments were initiated and maintained for 5 weeks. Identical studies were conducted concurrently in HCA2 (-/-) (niacin receptor(-/-)) mice. Niacin increased serum concentrations of the anti-inflammatory adipokine, adiponectin by 21% in HFD-fed wild-type mice, but had no effect on lean wild-type or lean or HFD-fed HCA2 (-/-) mice. Niacin increased adiponectin gene and protein expression in the HFD-fed wild-type mice only. The increases in adiponectin serum concentrations, gene and protein expression occurred independently of changes in expression of PPARgamma C/EBPalpha or SREBP-1c (key transcription factors known to positively regulate adiponectin gene transcription) in the adipose tissue. Further, niacin had no effect on adipose tissue expression of ERp44, Ero1-Lalpha, or DsbA-L (key ER chaperones involved in adiponectin production and secretion). However, niacin treatment attenuated HFD-induced increases in adipose tissue gene expression of MCP-1 and IL-1beta in the wild-type HFD-fed mice. Niacin also reduced the expression of the pro-inflammatory M1 macrophage marker CD11c in HFD-fed wild-type mice. Niacin treatment attenuates obesity-induced adipose tissue inflammation through increased adiponectin and anti-inflammatory cytokine expression and reduced pro-inflammatory cytokine expressio

Pharmacodynamics

Niacin is a B vitamin used to treat vitamin deficiencies as well as hyperlipidemia, dyslipidemia, hypertriglyceridemia, and to reduce the risk of myocardial infarctions. Niacin acts to decrease levels of very low density lipoproteins and low density lipoproteins, while increasing levels of high density lipoproteins. Niacin has a wide therapeutic window with usual oral doses between 500mg and 2000mg. Patients with diabetes, renal failure, uncontrolled hypothyroidism, and elderly patients taking niacin with simvastatin or lovastatin are at increased risk of myopathy and rhabdomyolysis.

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.