Pharmacology: Vitamins and Minerals

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Vitamin Ais essential for bone growth and the maintenance of epithelial tissues, skin, eyes, and hair. It has been used for the treatment of skin disorders such as acne.Vitamin Dhas a major role in regulating calcium and phosphorus metabolism and is needed for calcium absorption from the intestines.vitamin D2ergocalciferol (a synthetic fortified vitamin Dvitamin D3cholecalciferol (a natural form of vitamin D influenced by ultraviolet sunlight through the skin).calcifediolOnce absorbed, vitamin D is converted to ________(also known as 25- hydroxycholecalciferol) in the liver.Calcitriolthe active form of vitamin D, functions as a hormone and, with parathyroid hormone (PTH) and calcitonin, regulates calcium and phosphorus metabolism.Vitamin Ehas antioxidant properties that protect cellular components from being oxidized and red blood cells from hemolysis.Vitamin Koccurs in four forms;is needed for synthesis of prothrombin and the clotting factors VII, IX, and X.Vitamin K1 (phytonadione)is the most active form; called Mephyton and AquaMEPHYTONvitamin K2 (menaquinone)is synthesized by intestinal flora; not commercially availablevitamin K3(menadione)vitamin K4 (menadiol)have been produced synthetically.Vitamins K1 and K2are absorbed in the presence of bile salts.Vitamins K3 and K4do not need bile salts for absorption. after vitamin K is absorbed, it is stored primarily in the liver and in other tissues.Half of vitamin Kcomes from the intestinal flora, and the remaining portion comes from one's diet.vitamin K1 (phytonadione)For oral anticoagulant overdose,______ is the only vitamin K form available for therapeutic use and is most effective in preventing hemorrhage.Water-Soluble Vitaminsare the B-complex vitamins and vitamin C. This group of vitamins is not usually toxic unless taken in extremely excessive amounts.Vitamin B ComplexIt is a common group of vitamins administered in the clinical setting, especially to patients with alcoholism.Thiamine deficiencycan lead to the polyneuritis and cardiac pathology seen in beriberi or to Wernicke's encephalopathy that progresses to Korsakoff's syndrome, conditions most commonly associated with alcohol abuse.Wernicke-Korsakoff syndromeis a significant central nervous system disorder characterized by confusion, nystagmus, diplopia, ataxia, and loss of recent memory.IV administration of thiamineis recommended for treatment of Wernicke-Korsakoff syndrome. Thiamine must be given before giving any glucose to avoid aggravation of symptoms.Riboflavinmay be given to manage dermatologic problems such as scaly dermatitis, cracked corners of the mouth, and inflammation of the skin and tongue. To treat migraine headache, riboflavin is given in larger doses than for dermatologic concerns.Niacinis given to alleviate pellagra and hyperlipidemia, for which large doses are required. large doses may cause GI irritation and vasodilation, resulting in a flushing sensation.Pyridoxineis administered to correct vitamin B6 deficiency. It may also help alleviate the symptoms of neuritis caused by isoniazid (INH) therapy for tuberculosis.Pyridoxineis used to treat vitamin B6 deficiency caused by lack of adequate diet, inborn errors of metabolism, or drug-induced deficiencies secondary to INH, penicillamine, or cyclosporine (or hydralazine) therapy.Vitamin C (ascorbic acid)is absorbed from the small intestine. aids in the absorption of iron and in the conversion of folic acid.Folic Acid (Folate)is absorbed from the small intestine, and the active form of it is circulated to all tissues. One third of folate is stored in the liver, and the rest is stored in tissues. Eighty percent of folate is excreted in bile and 20% in urine.first trimester of pregnancyFolic acid deficiency during the _____ can affect the development of the central nervous system (CNS) of the fetus. This may cause neural tube defects (NTDs) such as spina bifida (defective closure of the bony structure of the spinal cord) or anencephaly (lack of brain mass formation).Vitamin B12like folic acid, is essential for DNA synthesis. Vitamin B12 aids in the conversion of folic acid to its active form. With active folic acid, vitamin B12 promotes cellular division. It is also needed for normal hematopoiesis (development of red blood cells in bone marrow) and to maintain nervous system integrity, especially the myelin.gastric parietal cellsproduce an intrinsic factor that is necessary for the absorption of vitamin B12 through the intestinal wall.mineralsVarious minerals, such as iron, copper, zinc, chromium, and selenium, are needed for body function.Ironis vital for hemoglobin regeneration.hemoglobinSixty percent of the iron in the body is found in5 to 20 mgA normal diet contains _______ per day.Iron toxicityis a serious cause of poisoning in children. Hemorrhage due to the ulcerogenic effects of unbound iron leads to shock.Copperis needed for the formation of RBCs and connective tissues. is a cofactor of many enzymes, and its function is in the production of the neurotransmitters norepinephrine and dopamine.Zincis important to many enzymatic reactions and is essential for normal growth and tissue repair, wound healing, and taste and smell.Chromiumis said to be helpful in the control of type 2 diabetes (non-insulin-dependent diabetes). It is thought that this mineral helps to normalize blood glucose by increasing the effects of insulin on the cells.Seleniumacts as a cofactor for an antioxidant enzyme that protects protein and nucleic acids from oxidative damageFluid and electrolyte balanceis necessary to maintain homeostasis. Intake must equal output to maintain fluid balance, and the body constantly strives for equilibrium.ECF compartmentis composed of plasma (intravascular), interstitial fluid (surrounding cells), and transcellular fluid, also known as the third-space (mucus and GI, cerebrospinal, pericardial, synovial, and ocular fluids).Electrolytesare substances that separate or dissociate into ions (charged particles) in solution; they are abundant in both ICF and ECF.CationIons carry either a positive chargeAnionIons carry either a negative chargeOsmolality and osmolarityare two different terms of measurement used to describe the number of osmoles or solutes in a solution.Osmolality- refers to the number of osmoles per kilogram of water and is expressed as mmol/kg (SI units) or mOsm/kg (conventional units) -is the concentration of fluid that affects the movement of water between compartments by osmosis.Osmolarity-is the number of osmoles in 1 L of solution and is expressed as mmol/L (SI units) or mOsm/L (conventional units).Iso-osmolar fluidhas the same proportion of weight of particles (e.g., sodium, glucose) and water.Hypo-osmolar fluidcontains fewer particles than water. -Hypo-osmolality of body fluid may be the result of excess water intake or fluid overload (edema) caused by an inability to excrete excess water.Hyperosmolar fluidcontains more particles than water. - Hyperosmolality of body fluid could be caused by severe diarrhea, increased salt and solutes (protein) intake, inadequate water intake, diabetes, ketoacidosis, or sweatingplasma/serum osmolality(concentration of circulating body fluids) can be calculated if the serum sodium level is known or the sodium, glucose, and BUN levels are known.Osmolalityrefers to the concentration of particles in a solution and is used in reference to body fluids.Tonicityis used primarily as a measurement of the concentration of IV solutions compared with the osmolality of body fluids.Intravenous Solutionsare ordered based on an evaluation of the patient's fluid and electrolyte balance, fluid requirements, and fluid needs. With fluid volume deficit (FVD) from the extracellular body compartment, fluid is lost from the interstitial and vascular spaces. Different types and concentrations of IVFs are available to replace body fluid losses.Crystalloidsontain fluids and electrolytes and are able to freely cross capillary walls. They do not contain any proteins, which are necessary to maintain the colloidal oncotic pressure that prevents water from leaving the intravascular space.Isotonic solutionshave the same approximate osmolality as ECF or plasma. Because of the osmotic equilibrium, water does not enter or leave the cell; therefore, there is no effect on red blood cells (RBCs). Isotonic solutions are primarily used for hydration and to expand ECF volume, because the fluid remains in the intravascular space.Hypotonic solutionsexert less osmotic pressure than ECF, which allows water to move into the cell. IV infusions of hypotonic solutions result in an increased solute concentration in the intravascular space,causing fluid to move into the intracellular and interstitial spaces. Excessive infusion of hypotonic solutions may cause hemolysis, decreased blood pressure, and decreased IVF volume.Hypertonic solutionsexert greater osmotic pressure than ECF, resulting in a higher solute concentration than the serum. When administered, hypertonic IVF fluids pull water from the interstitial space to the ECF via osmosis and cause cell shrinkage. Patients receiving hypertonic solutions must be monitored carefully for signs of circulatory overload (because of the increase in ECF volume).Dextrose solutionsprovide hydration and some calories and increase glucose levels in the blood. Dextrose solutions are also used to dilute IV medications for administration after compatibility between IVF and the medication has been verified. Dextrose may also affect the stability of some medication.Five-percent dextrose solutionsare hypertonic when added to normal saline or lactated Ringer's solution, but the remaining solution is isotonic because the dextrose is quickly metabolized to carbon dioxide and water.Sodium solutionsare available in various concentrations and tonicities.Isotonic solutionsare primarily used for hydration to expand the ECF and during blood product transfusions. Rapid infusion of isotonic saline solutions may lead to hypernatremia, fluid volume excess (FVE), and electrolyte depletion. Long-term use should also be avoided, as normal saline provides no caloriesHypotonic solutionsare also used for hydration and to treat hyperosmolar diabetes.Hypertonic saline solutionsare used to treat severe hyponatremia or hypochloremia; careful monitoring of electrolyte levels is important to avoid excess replacement.Balanced electrolyte solutionssuch as lactated Ringer's solution and Ringer's solution, contain electrolytes (no magnesium) and minimal calories with the addition of dextrose. Their primary use is hydration and electrolyte replacement. However, they do not provide adequate electrolytes for maintenance therapy for patients with limited or no oral intake.Lactated Ringer's solutionis similar in electrolyte content to plasma. Lactate is added as a buffering agent and is metabolized to bicarbonate. Complications of infusions of Ringer's and lactated Ringer's include fluid overload, excess electrolytes, and metabolic acidosis with long-term therapy. Because lactate is metabolized in the liver, lactated Ringer's is contraindicated for patients with liver diseaseColloidscontain protein or other large molecular substances that increase osmolarity without dissolving in the solution.plasma expanders.colloids are also known asBlood and blood productsinclude whole blood and the components that can be processed through centrifugation methods.Potassium (K+ )-is the major intracellular cation; 98% of the body's potassium is found within the cells, and 2% is found in the ECF.Hypokalemiaor potassium deficit, occurs with serum levels <3.5 mEq/L. Most cases of hypokalemia are caused by excessive loss rather than deficient intake.Hyperkalemiais defined as a serum potassium level >5.3 mEq/L; causes include excessive intake, decreased excretion, or shift from intracellular to extracellular space.Potassium-wasting diureticsare a major cause of hypokalemia.potassium-wasting (kaliuretic)excrete potassium and other electrolytes such as sodium and chloride in the urine.potassium-sparing (antikaliuretic) drugsretain potassium but excrete sodium and chloride in the urine.Sodiumis the major cation in the ECF135 to 145 mEq/L.The normal serum or plasma sodium level isHypernatremiaabove serum sodium level 145 mEq/LHyponatremiais caused by sodium loss, deficient intake, or water gain.Oral sodium replacementis the preferred treatment if the patient is able or if the deficit is mild. Sodium may also be replaced via enteral feeding tubes.Hypernatremiacan be caused by sodium gain, sodium retention, or water loss.Thirstis usually the first symptom of sodium deficit.Calciumis found in approximately equal proportions in ICF and ECF.acidoticWhen an individual is _____, calcium is released from serum protein, which increases serum iCa level.alkalosisWhen an individual is _____, calcium is bound to protein, and there is less iCa.decreasedIf serum albumin levels are ____, there is more free circulating calcium, even when the serum calcium level is decreased.Vitamin Dis needed for calcium absorption from the GI tract.Aspirin and anticonvulsantscan alter vitamin D, affecting calcium absorption. Loop or high-ceiling diuretics steroids (cortisone), magnesium preparations, and phosphate preparations promote calcium loss.HypocalcemiaInadequate calcium intake causes calcium to leave bone to maintain a normal serum calcium level.HypercalcemiaElevated serum calcium may be a result of hyperparathyroidism, malignancy, hypophosphatemia, excessive calcium intake, prolonged immobilization, multiple fractures, and drugs such as thiazide diuretics and steroids.Effect of Drugs on Calcium BalanceExcess calcium salt ingestion or infusion and thiazide and chlorthalidone diuretics can all contribute to an increased serum calcium level.Clinical Management of Calcium ImbalanceClinical management of hypocalcemia consists of oral supplements and IV calcium. Calcium carbonate can cause GI upset because it produces carbon dioxide. For better calcium absorption, calcium supplements should contain vitamin D, and oral calcium should be taken 30 minutes before meals.Magnesiumis most plentiful in the ICF.Magnesium deficitoften occurs with hypokalemia and hypocalcemia.hypomagnesemiamagnesium deficit.hypermagnesemiamagnesium excessChlorideis the principal anion of ECF.chloride ionis a major contributor to acid-base balance, gastric juice acidity, and the osmolality of ECF.Hypochloremiais a decreased serum chloride level.hyperchloremiais an elevated level.Phosphorusis found in both ICF and ECF but is the primary anion in ICF.phosphateThe majority of the body's phosphorus is found as-may lead to hemolytic anemia, platelet dysfunction, and reduced oxygen transport.Nutrientsare needed for cell growth, cellular function, enzyme activity, carbohydrate-fat-protein synthesis, muscular contraction, wound healing, immune competence, and gastrointestinal (GI) integrity.Inadequate nutrient intakecan result from surgery, trauma, malignancy, and other catabolic illnesses.ENTERAL NUTRITIONinvolves the GI tract, can be given orally or by feeding tubes (tube feeding). If the patient can swallow, nutrient preparations can be taken by mouth; if the patient is unable to swallow, a tube is inserted into the stomach or small intestine.PARENTERAL NUTRITIONinvolves administering high-caloric nutrients through large veins, for example, the subclavian vein. This method is called total parenteral nutrition (TPN), hyperalimentation (HA), or intravenous hyperalimentation (IVH).Total Parenteral Nutritionis the primary method for providing complete nutrients by the parenteral or IV route.Blenderizedare liquid in consistency, so they are able to pass through the tube. These are individually prepared based on the patient's nutritional need.polymeric (milk-based and lactose-free)The two groups of polymeric solutions are milk based and lactose free.elemental or monomericthe elemental or monomeric solutions are useful (e.g., Peptinex DT).Bolusfirst method used to deliver enteral feedings. 250 to 400 mL of solution is rapidly administered through a syringe or funnel into the tube four to six times a day.Intermittent drip or infusionadministered every 3 to 6 hours over 30 to 60 minutes by gravity drip or pump infusion.continuous dripprescribed for the critically ill or for those who receive feedings into the small intestine.cyclic infusionanother type of continuous feeding that is infused over 8 to 16 hours daily (day or night).Dehydrationcan occur if an insufficient amount of water is given with or between feedings.Aspiration pneumonitisis the major complication of enteral nutrition and may occur if the patient is fed while lying down or is unconscious.air embolismall central lines should have slide clamps on them to be closed completely when the solution bag and tubing are changed.Hyperglycemiaoccurs primarily as a result of the hypertonic dextrose solution of 20% or greater when TPN is initiated.Diarrheacaused by rapid administration of feeding, high caloric solutions, malnutrition, GI bacteria (Clostridium difficile)