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Vitamins. What are they?

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-Organic molecules needed in small quantities for normal metabolism and other biochemical functions, such as growth or repair of tissue - Attach to enzymes or coenzymes and help them activate anabolic (tissue-building) processes - Essential part of enzymatic reactions Natural sources from both plants and animals Insufficient amounts result in various deficiencies

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What are the vitamins that our own bodies synthesize?

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-Vitamin K and vitamin B complex obtained by synthesis by normal bacteria in the small intestine -Vitamin D can be synthesized by the skin when exposed to sunlight

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Water-Soluble Vitamins

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-( B-complex group and vitamin C) - Can be dissolved in water -Easily excreted in the urine -Cannot be stored by the body in large amounts - For these reasons Daily intake required to prevent deficiencies

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Fat-Soluble Vitamins

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- ( Vitamins A, D, E, K) - Present in both plant and animal foods -Stored in the liver and fatty tissues - Slow metabolism -Excreted via the feces -Daily intake not required -Deficiency occurs only after prolonged deprivation -Can become toxic if excessive amounts are consumed

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In what situation is megadosing known to be helpful?

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1- When concurrent long-term drug therapy depletes vitamin stores or otherwise interferes with the function of a vitamin. ( for example giving Vitamin B6 to patients taking izoniazid for TB) 2- gastrointestinal malabsorption syndromes ( severe colitis and CF) 3- pernicious anemia, which results from cyanocobalamin (vitamin B12) deficiency. 4- When the vitamin acts as a drug when megadosed For example Niacin ( Vitamin B3) used to lower cholesterol. At 20mg its a vitamin, at dosages 50-100 higher is used to lower cholesterol.

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Toxic hypervitaminosis

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-vitamin megadosing can lead to toxic accumulations known as hypervitaminosis, especially with the fat-soluble vitamins A, D, and K - Vitamin E appears safer, however, even at doses 10 to 20 times the recommended DRI. - Hypervitaminosis is much less likely to occur with the water-soluble vitamins (B complex and C) -Nevertheless, it is known that megadosing with vitamin B6 (pyridoxine) at 50 to 100 times the DRI can cause nerve damage. - People will illnesses may be the least able to tolerate megadosing. may be more of a strain for a gastrointestinal tract that is already weakened by illness. Megadosing can even interfere with chemotherapy drugs as well as radiation treatments ( vitamins are antioxidating, and chemo works by oxidating)

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RDAs DRIs Percentage Daily Values

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RDAs ( Recommended daily allowance): represents minimum nutrient requirements DRIs ( Dietary reference intakes): represents optimal nutrient amounts for good health. Percentage daily values: values that appear on the mandatory labels of commercial food products and indicate what percentage of the DRI for a specific nutrient is met by a single serving of the food product.

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Vitamin A Mechanism of Action and drug effects

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Vitamin A ( Retinol) Food sources: Liver; fish; dairy products; egg yolks; dark green, leafy, yellow-orange vegetables and fruits ( carotenes) Mechanism of action and drug effects: - Essential for night and normal vision ( because it is part of the major retinal pigments called rhodopsin) -Required for growth and development of bones and teeth ( retinoic acid) - Necessary for other processes: Reproduction, Integrity of mucosal and epithelial surfaces, Cholesterol and steroid synthesis and - essential for normal cell growth and differentiation and for the development of the physical shapes of the body's many parts—a process known as morphogenesis.

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Vitamin A indications and deficiency symptoms

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Indications: -Dietary supplement Infants and pregnant and nursing women - used for Skin conditions Acne, psoriasis, keratosis follicularis ( isotretonoin) -Deficiency symptoms: Hyperkeratosis of the skin Night blindness Other conditions

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Vitamin A Adverse Effects with long term excessive use

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Central nervous: Headache, increased intracranial pressure, lethargy, malaise Gastrointestinal: Nausea, vomiting, anorexia, abdominal pain, jaundice Integumentary: Dry skin, pruritus, increased pigmentation, night sweats Metabolic: Hypomenorrhea, hypercalcemia Musculoskeletal: Arthralgia, retarded growth

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Vitamin A: Toxicity

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- occurs most commonly in children - Ingestion of excessive amounts causes toxicity : -Irritability, drowsiness, vertigo, delirium, vomiting, other symptoms -Increased intracranial pressure in infants (bulging fontanelles) -Generalized peeling of the skin and erythema over several weeks only treatment is to discontinuation of the drug

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Vitamin A interactions

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-less when used together with lubricant laxatives and cholestyramine. - concurrent use of isotretinoin and vitamin A supplementation can result in additive effects and possibly toxicity. All vitamin As are pregnancy A by the way

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Vitamin D

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" sunshine vitamin" Food sources ( D2): Dairy products, fortified cereals and fortified orange juice, liver, fish liver oils, saltwater fish, butter, eggs - Fat soluble -Responsible for proper utilization of calcium and phosphorus. Necessary for normal calcification of bone and teeth -Actually a group of analog steroid chemicals -Different chemicals, produce same effect -Vitamin D2 (ergocalciferol) Plant vitamin D Obtained through dietary sources -Vitamin D3 (cholecalciferol) Produced in the skin by ultraviolet irradiation (sunshine)

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Vitamin D: Indications

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-Dietary supplement -Treatment of vitamin D deficiency -Treatment and correction of conditions related to long-term deficiency: rickets, tetany, osteomalacia -Prevention of osteoporosis Other uses: hypocalcemia, hypophosphatemia, hypparathrydoism , pseudohypoparathyroidism

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Rickets symptoms

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Symptoms include soft, pliable bones, which causes deformities such as bowlegs and knock knees; nodular enlargement on the ends and sides of the bones; muscle pain; enlarged skull; chest deformities; spinal curvature; enlargement of the liver and spleen; profuse sweating; and general tenderness of the body when touched.

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Vitamin D Contraindications

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known allergy to the product, hypercalcemia, renal dysfunction, and hyperphosphatemia.

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Vitamin D Toxicity

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most commonly occurs in children -The amount of vitamin D considered to be toxic varies considerably among individuals but is generally thought to be 1.25 to 2.5 mg of ergocalciferol daily in adults and 25 mcg daily in infants and children. - The toxic effects of vitamin D are those associated with hypertension, such as weakness, fatigue, headache, anorexia, dry mouth, metallic taste, nausea, vomiting, abdominal cramps, ataxia, and bone pain. If not recognized and treated, these symptoms can progress to impairment of renal function and osteoporosis.

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Vitamin D interactions

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Reduced absorption of vitamin D occurs with the concurrent use of lubricant laxatives and cholestyramine. Patients taking digitalis preparations can develop cardiac dysrhythmias as a result of excessive vitamin D intake.

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Vitamin D forms -calcifediol (Calderol) -calcitriol (Rocaltrol) -dihydrotachysterol (Hytakerol) -ergocalciferol (Drisdol)

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- Generally considered to be Pregnancy A or B calcifediol (Calderol) - Vitamin D3 - used primarily for the management of hypocalcemia in patients with chronic renal failure who are undergoing hemodialysis. - Calcifediol is also used for signs of hyperparathyroid disease. calcitriol (Rocaltrol) - Vitamin D3 -used for the management of hypocalcemia in patients with chronic renal failure who are undergoing hemodialysis. - It is also used in the treatment of hypoparathyroidism and pseudohypoparathyroidism, vitamin D-dependent rickets, hypophosphatemia, and hypocalcemia in premature infants. dihydrotachysterol (Hytakerol) -administered orally once daily for the treatment of any of the previously mentioned conditions - Intramuscular use is indicated for patients with gastrointestinal, liver, or biliary disease associated with malabsorption of vitamin D analogues. ergocalciferol (Drisdol) -indicated for use in patients with gastrointestinal, liver, or biliary disease associated with malabsorption of vitamin D analogues.

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Vitamin E SOurces and Mechanism of Action

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-Fat soluble -Tocopherols ( alpha, beta. gamma and delta) make up vitamin E compounds. -Dietary plant sources Fruits, grains, fortified cereals, vegetable oils, wheat germ, nuts -Animal sources Eggs, chicken, meats, fish -Exact biologic function of vitamin E is unknown Believed to act as an antioxidant

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Vitamin E: Indications

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-Dietary supplement -Antioxidant -Treatment of deficiency: Highest risk of deficiency in premature infants symptoms of of Vitamin E deficiency in premies: irritability, edema, thrombosis and hemolytic anemia.

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Vitamin E: Adverse Effects

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Very few acute adverse effects: Relatively nontoxic CNS effects: Fatigue, headache, blurred vision GI tract: Nausea, diarrhea, flatulence

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Vitamin K Sources and Mechanism of action

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-Fat soluble -Three types: K1, K2, K3 -Dietary sources of K1 Green leafy vegetables (broccoli, cabbage, spinach, kale), cheese, soybean oils -Vitamin K2 synthesized by intestinal flora -Essential for synthesis of blood coagulation factors in the liver -Vitamin K-dependent clotting factors: II VII IX X

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Vitamin K: Indications

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-Dietary supplementation -Treatment of deficiency states (rare) Antibiotic therapy Malabsorption -Given prophylactically to newborn infants -Reverses the effects of certain anticoagulants (warfarin)

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Vitamin K Toxicity

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-Toxicity is primarily limited to use in the newborn. -Hemolysis of red blood cells (RBCs) can occur, especially in infants with low levels of glucose-6-phosphate dehydrogenase. -In severe cases, replacement with blood products may be indicated.

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Forms of Vitamin K - Vitamin K1 (phytonadione)

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Because of its potential to cause anaphylaxis (due to the formulation), for intravenous use it is usually diluted and given over 30 to 60 minutes. Vitamin K should be given subcutaneously and not intramuscularly when used to reverse warfarin effects.

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Vitamin B1 (Thiamine) Function

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- Vitamin B1 (thiamine) is an essential precursor for the formation of thiamine pyrophosphate. - This is required for the citric acid cycle (Krebs cycle), a major part of carbohydrate metabolism, as well as several other metabolic pathways

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Vitamin B1 ( Thiamine) Sources

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-Water soluble -Food sources: Enriched whole grain breads and cereals, liver, beans, yeast

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Vitamin B1 (Thiamine): Deficiencies

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-Beriberi Brain lesions, polyneuropathy of peripheral nerves, serous effusions, cardiac anatomic changes -Wernicke's encephalopathy Also known as cerebral beriberi

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Vitamin B1 (Thiamine): Causes of Deficiencies

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-Poor diet -Extended fever -Hyperthyroidism -Liver disease -Alcoholism -Malabsorption -Pregnancy and breast-feeding

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Vitamin B1 (Thiamine): Functions

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-Essential for: Carbohydrate metabolism Many metabolic pathways, including Krebs cycle -Maintains integrity of: Peripheral nervous system Cardiovascular system GI tract

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Vitamin B1 (Thiamine): Indications

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-Treatment of thiamine deficiency: Beriberi Wernicke's encephalopathy Peripheral neuritis associated with pellagra ( vitamin B3 - Niacin- deficiency) and neuritis associated with pregnancy - metabolic disorders: subacute necrotizing encephalomyelopathy, maple syrup urine disease, and lactic acidosis associated with pyruvate carboxylase enzyme deficiency and hyper-beta-alaninemia. -Dietary supplement Malabsorption induced by alcoholism, cirrhosis, GI disease -Oral insect repellant

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Vitamin B2 (Riboflavin) food sources

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-Water soluble -Food sources: Green leafy vegetables Eggs, dairy products Nuts, legumes Meats, liver Yeast, enriched whole-grain products

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Vitamin B2 (Riboflavin): Causes of Deficiency and symptoms

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-Alcoholism is a major cause*** -Deficiency also caused by: Intestinal malabsorption Long-term infections Liver disease Malignancy Probenecid therapy Signs and symptoms: A deficiency of vitamin B2 (riboflavin) results in cutaneous, oral, and corneal changes that include cheilosis (chapped or fissured lips), seborrheic dermatitis, and keratitis.

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Vitamin B2 (Riboflavin): Functions

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-Converted into enzymes essential for tissue respiration -Required to activate vitamin B6 (pyridoxine) -Converts tryptophan into niacin -Maintains erythrocyte integrity

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Vitamin B2 (Riboflavin): Indications

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-Dietary supplement -Treatment of deficiency -Microcytic anemia -Acne -Migraine headaches -Many other uses

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Vitamin B2 (Riboflavin): Adverse Effects

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No adverse or toxic effects Large doses will discolor urine to a yellow-orange

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Vitamin B3 ( Niacin) Sources

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-Water soluble -Food sources: Beans, turkey, tuna, liver, yeast Enriched whole-grain breads and cereals, wheat germ -Also synthesized from tryptophan (an essential amino acid obtained from protein digestion)

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Vitamin B3 (Niacin): Functions

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-Once ingested, converted to nicotinamide -Nicotinamide is converted to two coenzymes -These enzymes are required for: --Glycogenolysis ( breakdown of stored glycogen into usable glucose), tissue respiration --Lipid, protein, and purine metabolism

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Vitamin B3 (Niacin): Indications

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- Prevention/ treatment of pellagra ( deficiency of vitamin B3) that is most commonly the result of malabsorption. -Antihyperlipidemic drug: doses required much higher than required for nutritional purposes

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Vitamin B3 (Niacin): Deficiency

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.Pellagra: niacin deficiency Mental: various psychotic symptoms Neurologic: neurasthenic syndrome Cutaneous: crusting, erythema Inflammation of mucous membranes: oral, vaginal, and urethral lesions; glossitis GI: diarrhea or bloody diarrhea

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Vitamin B3 (Niacin): Adverse Effects

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-Adverse effects seen when higher doses are used in the treatment of hyperlipidemia: Flushing Pruritus GI distress

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Vitamin B6 (Pyridoxine) Sources

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-Water soluble -Sources: Whole grains, wheat germ, yeast Fish, organ meats, poultry, meats, eggs Peanuts, nuts, vegetables, bananas

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Vitamin B6 (Pyridoxine) composed of three compounds: ?

answer

-Pyridoxine -Pyridoxal -Pyridoxamine

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Vitamin B6 (Pyridoxine): Function

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-Necessary for many metabolic functions: Protein, lipid, and carbohydrate utilization Conversion of tryptophan to niacin -Necessary for integrity of peripheral nerves, skin, mucous membranes, hematopoietic system - conversion of the amino acid tryptophan to niacin (vitamin B3) and the neurotransmitter serotonin. - also essential in the synthesis of gamma-aminobutyric acid, an inhibitory neurotransmitter in the CNS.

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Vitamin B6 (Pyridoxine): Deficiency Signs and Symptoms

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-Signs and symptoms: Sideroblastic anemia Neurologic disturbances Seborrheic dermatitis Cheilosis (chapped, fissured lips) Glossitis, stomatitis, Epileptiform convulsions Hypochromic microcytic anemia convulsions ( especially neonates and infants)

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Vitamin B6 (Pyridoxine): Causes of Deficiency

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-Inadequate intake -Poor absorption -Uremia, alcoholism, cirrhosis, hyperthyroidism, malabsorption, heart failure -Drug induced (isoniazid, hydralazine, others)

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Vitamin B6 (Pyridoxine): Indications

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Used to prevent and treat deficiency book also says: - seizures ( unresponsive to other therapies) - Morning sickness

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Vitamin B6 (Pyridoxine): Toxicity

answer

Toxic effects occur with large doses, especially neurotoxicity. Will subsided when discontinued Central nervous: Paresthesias, flushing, warmth, headache, lethargy

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Vitamin B12 (Cyanocobalamin) Sources

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-Water soluble -Synthesized by microorganisms present in the body -Food sources: Liver, kidney, fish, shellfish, poultry, milk Eggs, blue cheese, fortified cereals -Contained in minimal amounts in plants

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Vitamin B12 (Cyanocobalamin): Function

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-Present as two different coenzymes -Required for many metabolic pathways: Fat and carbohydrate metabolism Protein synthesis Growth, cell replication Hematopoiesis Nucleoprotein and myelin synthesis note: The cells that have the greatest requirement for vitamin B12 are those that divide rapidly, such as epithelial cells, bone marrow, and myeloid cells.

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Vitamin B12 (Cyanocobalamin): Deficiency Symptoms and Causes

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Symptoms: - GI lesions, neurologic changes that result in degenerative CNS lesions . Pernicious anemia.( can lead to megaloblastic anemia if not treated by taking Vitamin B12 via deep intramuscular route) Causes: - Major cause is malabsorption - less likely causes are poor diet ( strict vegetarian diet), alcoholism and chronic hemorrhage

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Vitamin B12 (Cyanocobalamin): Oral Absorption

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-Oral absorption of vitamin B12 (extrinsic factor) requires presence of the intrinsic factor -The intrinsic factor is a glycoprotein secreted from the gastric parietal cells -The extrinsic and intrinsic factors form a complex that is then absorbed by the intestines

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Vitamin B12 (Cyanocobalamin): Contraindications and Adverse effects

answer

- known drug product allergy. This may include sensitivity to the chemical element cobalt, which is part of the structure of cyanocobalamin. -hereditary optic nerve atrophy (Leber's disease). Adverse Effects: - Vitamin B12 is nontoxic, and large doses must be ingested to produce adverse effects, which include itching, transitory diarrhea, and fever.

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Vitamin C (Ascorbic Acid) Sources

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-Water soluble -Natural sources: Citrus fruits and juices, strawberries Tomatoes, potatoes Broccoli, spinach, Brussels sprouts Cabbage, green peppers Liver -Can also be synthesized

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Vitamin C (Ascorbic Acid): Functions

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-Acts in oxidation-reduction reactions -Required for several metabolic activities: Collagen synthesis Maintenance of connective tissue Tissue repair Maintenance of bone, teeth, and capillaries Folic acid metabolism Erythropoiesis - Enhances absorption of iron -Required for the synthesis of: Lipids Proteins Steroids -Aids in cellular respiration -Aids in resistance to infection

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Vitamin C (Ascorbic Acid): Deficiency

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.Prolonged deficiency results in scurvy: --Gingivitis and bleeding gums --Loss of teeth --Anemia --Subcutaneous hemorrhage --Bone lesions --Delayed healing of soft tissues and bones

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Vitamin C (Ascorbic Acid): Indications

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-Dietary supplement -Prevention and treatment of scurvy -Urinary acidifier

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Vitamin C (Ascorbic Acid): Megadoses

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Megadoses may cause: -Nausea, vomiting, headache, abdominal cramps Acidified urine, with possible stone formation Discontinuing megadoses may result in scurvy-like symptoms

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What are minerals?

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-Inorganic elements or salts -Bind with enzymes or other organic molecules -Help to regulate many bodily functions - act as building blocks for many body structures - also needed for ICF and ECF electrolytes Macrominerals ( needed in large amounts) Microminerals, or trace elements ( required in smaller amounts)

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Calcium - concentration and absorption

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Most abundant mineral element in the body Accounts for 2% of body weight Highest concentration in bones and teeth Efficient absorption requires adequate amounts of vitamin D

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Calcium: Food Sources

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-Found in many foods: Especially milk and dairy products Fortified cereals Calcium-fortified orange juice Sardines, salmon

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Calcium requirements are high for who?

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Growing children Women who are pregnant or breast-feeding

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Calcium: Function

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-Essential for normal maintenance and function of: Nervous, muscular, skeletal systems Cell membrane and capillary permeability -Catalyst in many enzymatic reactions -Essential in many physiologic processes: Transmission of nerve impulses Contraction of cardiac, smooth, and skeletal muscles Renal function, respiration, and blood coagulation ( cofactor in clotting reactions)

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Calcium Deficiency states

answer

-Infantile rickets -Adult osteomalacia -Osteoporosis - tetany - muscle cramps - renal insufficiency

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Calcium: Causes of Deficiency

answer

-Inadequate intake of calcium or vitamin D -Hypoparathyroidism -Malabsorption syndrome

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Calcium: Indications

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Used to treat various deficiency states Dietary supplement for women during pregnancy and lactation

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Calcium: Toxicity

answer

-Hypercalcemia may occur with therapy: Anorexia Nausea Vomiting Constipation -Severe hypercalcemia can cause: Cardiac irregularities Delirium Coma management of acute hypercalcemia may require hemodialysis

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Calcium: Drug Interactions*

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-Calcium salts will bind (chelate) with tetracyclines to produce an insoluble complex - If hypercalcemia is present in patients taking digitalis preparations, serious cardiac dysrhythmias can occur.

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Calcium different forms: uses Calcium chloride Calcium carbonate and calcium citrate Calcium acetate

answer

Calcium chloride - treatment of cardiac arrest and hypocalcemic tetany Calcium carbonate (tums) and calcium citrate ( citracal) - used as antacids and are also used to treat or prevent calcium deficiency and to treat hyperphosphatemia. Calcium acetate (Phoslo) - is NOT used for calcium replacement. It is used only to control hyperphosphatemia in patients with end-stage renal disease

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Magnesium: Function

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-One of the principal cations of intracellular fluid -Essential for enzyme systems associated with energy metabolism -Required for: Nerve physiology Muscle contraction - produces an anticonvulsant effect by inhibiting neuromuscular transmission in selected convulsive states

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Magnesium Sources

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-Dietary sources : Green leafy vegetables Meats, seafood, milk, cheese, yogurt Bran cereal, nuts -Required in higher amounts for those with diets high in protein-rich foods, calcium, and phosphorus

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Magnesium: Causes of Deficiency

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Malabsorption Alcoholism Long-term IV feedings Diuretics Metabolic disorders (hyperthyroidism, diabetic ketoacidosis)

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Magnesium: Indications

answer

-Nutritional supplement -Treatment of magnesium deficiency -Anticonvulsant in magnesium deficiency -Preeclampsia and eclampsia -Tocolytic drug for inhibition of uterine contractions in premature labor -Cardiac dysrhythmias - short term treatment of constipation

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Magnesium: Adverse Effects

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Adverse effects caused by hypermagnesemia: -Tendon reflex loss -Difficult bowel movements -CNS depression -Respiratory distress -Heart block -Hypothermias note: has additive CNS depressant effects when taken with CNS depressants and neuromuscular blocking drug

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Phosphorus

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Widely distributed in foods: -Milk -Yogurt -Cheese -Peas -Meat -Fish -Eggs Dietary deficiency is rare

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Phosphorus Deficiency

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Deficiency caused by nondietary causes: -Malabsorption -Extensive diarrhea or vomiting -Hyperthyroidism -Long-term use of aluminum or calcium antacids -Hepatic disease

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Phosphorus: Functions

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-Required precursor for the synthesis of essential body chemicals -Building block for body structures -Required for the synthesis of: Nucleic acid ADP AMP ATP -Responsible for cellular energy transfer -Necessary for the development and maintenance of the skeletal system and teeth

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Phosphorus: Adverse Effects

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-Diarrhea -Nausea and vomiting -Other GI disturbances -Confusion -Weakness -Breathing difficulties NOTE: contraindicated in HYPOcalcemia ( due to inverse relationship)

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Zinc Functions

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-Trace element -Essential in metabolic reactions of proteins and carbohydrates -Important for normal tissue growth and repair, especially wound repair

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Zinc Sources

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Found in: Red meats, liver, oysters, milk products, eggs, beans, nuts, whole grains, fortified cereals, certain seafoods

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Nursing Implications

answer

-Assess nutritional status -Assess baseline lab values (H&H, WBC, RBC, protein, albumin levels) - Follow specific guidelines for administration, especially if parenteral -Provide nutritional counseling about necessary foods to include in the diet -

Pharmacology Chapter 53 Vitamins and Minerals – Flashcards

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