Renal Agents PDF

DRUGS ACTING ON THE URINARY SYSTEM Anngeo D. Labog, RN, MAN Henry T. Barriga Jr., RN, MN Tracey Joy L. Dela Cruz, RN, MAN Michael Francis T. Cahandig, RN, MN STUDENT LEARNING OUTCOME That within my 1 - hour span of discussion, the students will be able to: a. review...

DRUGS ACTING ON THE URINARY SYSTEM Anngeo D. Labog, RN, MAN Henry T. Barriga Jr., RN, MN Tracey Joy L. Dela Cruz, RN, MAN Michael Francis T. Cahandig, RN, MN STUDENT LEARNING OUTCOME That within my 1 - hour span of discussion, the students will be able to: a. review their knowledge on kidney structure and functions; b. explain the actions and uses of diuretics; c. identify various groups of diuretics; d. describe several side effects and adverse reactions related to potassium wasting and potassium sparing diuretics; and e. explain the nursing interventions including client teaching related to potassium wasting and potassium sparing diuretics.  DRUGS ACTING ON THE URINARY SYSTEM  RENAL SYSTEM RENAL SYSTEM Kidneys § Filter physiologically essential substances (sodium, potassium ions) from the blood and selectively reabsorb those substances that are needed to maintain the normal composition of internal body fluids. § Multilobular structure, composed of up to 18 lobes, each lobule is composed of nephrons (functional unit). RENAL SYSTEM Nephron § Each kidney is composed of more than 1 million tiny, closely packed functional units called nephron. § Each nephron has a glomerulus (filters blood) and a tubular component. Glomerulus § Consists of a compact tuft of capillaries encased in a thin, double- walled capsule (Bowman’s Capsule).  RENAL SYSTEM TUBULAR COMPONENTS OF THE NEPHRON Four segments: Proximal Convoluted Tubule Loop of Henle Distal Convoluted Tubule Collecting Tubule  RENAL SYSTEM Proximal Convoluted Tubule o Highly coiled segment, located in the kidney’s cortex o Drains Bowman’s Capsule, responsible for the reabsorption of the majority of ultrafiltrate. o Majority of the water, sodium, potassium, chloride, calcium, phosphate, bicarbonate, urea, as well as the glucose and amino acids are reabsorbed from the ultrafiltrate made by the glomerulus back into the bloodstream.  RENAL SYSTEM Loop of Henle Thin, looped structure, absorbs even more water Three Different Parts: Thin Descending Limb of Henle Very permeable to water, allows reabsorption of water back into the blood. Thin Ascending Limb of Henle Thick Ascending Limb of Henle Both are not permeable to water; reabsorb ions like sodium, potassium, chloride and calcium. RENAL SYSTEM Distal Convoluted Tubule - Distal coiled segment Collecting Tubule - Final segment DIURETICS A diuretic is any substance that promotes an increase in the amount of urine and salt excretion. It generally reduces the amount of fluid in the blood which will then be deposited as urine. DIURETICS Increases urine flow (diuresis) by inhibiting sodium and water reabsorption from the kidney tubules. TWO Main Purpose: 1. Decrease Hypertension 2. Decrease Edema (Peripheral and Pulmonary) Antihypertensive Effect: Promote sodium and water loss by blocking the sodium and chloride reabsorption, causing decrease in fluid volume and lowering blood pressure. DIURETICS Common conditions that are treated with diuretics are: ü Pulmonary and Systemic (Cardiovascular) Congestive Disorders ü Hypertension ü Increased Intracranial Pressure ü Increased IOP ü Edema  DIURETICS FIVE Categories Effective in Removing Water and Sodium: 1. Thiazide and Thiazide-like 2. Loop or high ceiling 3. Osmotic 4. Carbonic Anhydrase Inhibitor 5. Potassium sparing Natriuresis: sodium loss in the urine  Thiazide, Loop and potassium sparing are the most frequently prescribed types for hypertension and for edema associated with CHF. First four categories are all potassium DIURETICS wasting except fifth. Potassium Wasting Diuretics: promote potassium excretion Potassium Sparing Diuretics: promote potassium retention I. THIAZIDE AND THIAZIDE-LIKE DIURETICS Example: Hydrochlorothiazide (Apo-hydro) Chlorothiazide (Diuril) They act directly on the kidneys and promote urine flow by inhibiting the sodium/chloride reabsorption located in the distal convoluted tubule resulting in the excretion of sodium, potassium and hydrogen ions but also inhibits calcium loss. I. THIAZIDE AND THIAZIDE-LIKE DIURETICS HYDROCHLOROTHIAZIDE Therapeutic Effects/ Uses: o To increase urine output, to treat hypertension, edema from CHF, hepatic cirrhosis, and renal dysfunction. Mode of Action: o Action is on the renal distal tubules by promoting sodium, potassium and water excretion, decreasing preload and cardiac output, also decreases edema, acts on arterioles, causing vasodilation thus decreasing BP.  I. THIAZIDE AND THIAZIDE-LIKE DIURETICS q PHARMACOKINETICS q PHARMACODYNAMICS § Absorption § PO § Readily absorbed from the GI Tract § ONSET 2 hours § Distribution § PEAK 3 – 6 hours § PB: 65% § DURATION 6 – 12 hours § Metabolism § t ½ : 6 – 15 hours § Excretion § In urine  I. THIAZIDE AND THIAZIDE-LIKE DIURETICS q SIDE EFFECTS q ADVERSE EFFECTS § Dizziness § Severe Dehydration § Vertigo § Hypotension § Weakness § Severe potassium depletion § Nausea § Vomiting § Diarrhea § Hyperglycemia § Constipation § Rash § Photosensitivity I. THIAZIDE AND THIAZIDE-LIKE DIURETICS ASSESSMENT § Assess VS, weight, urine output & serum chemistry values (electrolytes, glucose, uric acid) for baseline levels. § Check peripheral extremities for edema. § Obtain history of drugs and herbs taken daily. DIAGNOSIS § Risk for Fluid Volume Deficit § Impaired Patterns of Urinary Elimination  I. THIAZIDE AND THIAZIDE-LIKE DIURETICS PLANNING § Client’s BP will decrease and/ or return to normal value. § Client’s edema will decrease. § Client’s serum chemistry levels remain within normal range. INTERVENTIONS § Monitor VS & Serum Electrolytes esp. potassium, glucose, SUA and Cholesterol levels. § Observe for signs and symptoms of hypokalemia.  I. THIAZIDE AND THIAZIDE-LIKE DIURETICS INTERVENTIONS o Check the client’s weight daily at a specified time. Weight gain of 2.2 to 2.5 lbs. is equivalent to an excess liter of body fluids. o Monitor UO to determine fluid loss/ retention. o Suggest to take the drug early in the morning to avoid sleep disturbance resulting form nocturia. o Keep drugs out of reach of children. Request childproof bottle. o Instruct client to slowly change positions from lying to standing. o Instruct to check blood sugar level when taking large doses of the drug. o Advise client to use sunblock when in direct sunlight. o Instruct to eat food high in potassium. Potassium supplements may be necessary. o Instruct to take drugs with food. II. LOOP DIURETICS o Act on the ascending loop of Henle by inhibiting chloride transport of sodium into the circulation. o Effect are dose related (increase dose, increases the effect and response of drug, response in known as high ceiling diuretics). o Have a great saluteric (sodium- losing) effect and can cause rapid diuresis thus decreasing vascular fluid volume causing decrease in cardiac output and BP.  II. LOOP DIURETICS I. FUROSEMIDE Therapeutic Effects/ Uses: o To treat fluid retention/ fluid overload caused by CHF, renal dysfunction, cirrhosis, hypertension and acute pulmonary edema. Mode of Action: o Inhibits the sodium and water reabsorption from the Loop of Henle and distal renal tubules; potassium, magnesium and calcium also may be excreted.  q PHARMACOKINETICS q PHARMACODYNAMICS Absorption PO o PO tablet: Readily absorbed in o ONSET < 60 minutes the GI Tract o PEAK 1 – 4 hours II. LOOP Distribution o DURATION 6 – 8 hours DIURETICS o PB: 95% IV o ONSET 5 minutes Metabolism o PEAK 20 – 30 minutes o t ½ : 30 – 50 minutes o DURATION 2 hours Excretion o In urine; some in feces  II. LOOP DIURETICS q SIDE EFFECTS q ADVERSE EFFECTS § Nausea § Severe Dehydration § Diarrhea § Marked Hypotension § Electrolyte Imbalance § Renal Failure § Vertigo § Cramping § Headache § Ototoxicity § Dizziness § ECG changes § Rash § Photosensitivity  II. LOOP DIURETICS ASSESSMENT o Assess VS, weight, UO & serum electrolytes values for baseline levels. o Furosemide is a highly protein bound drug, can displace other protein bound drugs (warfarin). o Obtain history of drugs and herbs taken daily. DIAGNOSIS o Risk for Fluid Volume Deficit  II. LOOP DIURETICS PLANNING o Client’s edema and/ or hypertension will decrease. o Client’s serum chemistry levels remain within normal range. INTERVENTIONS o Check the half life, with shorter half-life, can be repeated or given more than once a day. o Check onset of action, if given IV, UO should increase in 5 to 20 minutes. If UO does not increase, notify Physician. May be with severe renal d/o. o Monitor I & O, to determine fluid gain and loss. o Monitor VS especially the BP. o Administer IV Furosemide slowly, hearing loss may occur if rapidly given.  II. LOOP DIURETICS NURSING INTERVENTIONS o Check the client’s weight daily at a specified time. Weight gain of 2.2 to 2.5 lbs. is equivalent to an excess liter of body fluids. o Observe for signs of Hypokalemia (muscle weakness, abdominal distention, leg cramps, cardiac dysrhythmias). o Check serum potassium levels especially when a client is taking digoxin. o Suggest to take the drug early in the morning to avoid sleep disturbance resulting form nocturia. o Instruct to rise slowly to prevent dizziness resulting from fluid loss. o Suggest to take the drug with food to prevent nausea. II. LOOP DIURETICS III. OSMOTIC DIURETICS o Increase the osmolality (concentration) of the plasma and fluid in the renal tubules. o Sodium, chloride, potassium (to a lesser degree), and water are excreted. o Used to prevent Kidney Failure, to decrease intracranial pressure (cerebral edema), intraocular pressure (glaucoma). III. OSMOTIC DIURETICS o Mannitol is a potent osmotic potassium-wasting diuretic frequently used in emergency situations such as ICP and IOP. o It is a strong hydrophilic substance that is very high in tonicity (absorbs fluid from blood plasma) and is easily filtered out through the glomerulus with little reabsorption and thus increase urinary output via osmosis. o Diuresis occurs within 1 to 3 hours after IV administration. o Side effects and adverse reaction of Mannitol include fluid and electrolyte imbalance, pulmonary edema from rapid shifts of fluids, nausea, vomiting, tachycardia from rapid fluid loss and acidosis. III. OSMOTIC DIURETICS Mannitol may be used in diverse clinical settings, such as: o Decreasing intracranial pressure and IOP in patients with intracranial trauma and glaucoma respectively. Mannitol increases glomerular filtration rate (GFR), possibly by a deswelling effect on tubular cells. o It increases renal blood flow and maintains filtration fraction and oxygenation in postoperative Acute Kidney Injury (AKI).  III. OSMOTIC DIURETICS Nursing Considerations: o Crystallization of mannitol in the bottle may occur when the drug is exposed to a low temperature. o The bottle should be warmed to dissolve the crystals. o Inspect for crystals prior to administration. If crystals are visible, re-dissolve by warming the solution up to 37°C o The solution should not be used for IV infusion if crystals are present and have not been dissolved. o IV infusion of mannitol can be administered over 30 mins - 1 hour, a continuous a rate sufficient to maintain desire urine output at 150 to 500 mL/hour. IV. CARBONIC ANHYDRASE INHIBITORS o Block the action of the enzyme carbonic anhydrase which is needed to maintain acid base balance. o Inhibition of this enzyme causes increase Sodium, potassium and bicarbonate excretion. o Metabolic acidosis may occur if prolonged used. o Used primarily to decrease IOP in Open angle Glaucoma. o acetazolamide, dichlorphenamide, ethoxzolamide, methazolamide  q SIDE EFFECTS q ADVERSE EFFECTS § Nausea § Fluid and § Vomiting Electrolyte IV. CARBONIC § Metabolic imbalance § Hemolytic ANHYDRASE acidosis anemia § Anorexia INHIBITORS § Confusion § Orthostatic hypotension V. POTASSIUM SPARING DIURETICS o Potassium Sparing Diuretics also works as an antagonist at the aldosterone receptor which will result to decrease in blood pressure. o This type of diuretic is commonly used in combination with other diuretics. o Weaker than thiazides and loop diuretics. o Used as mild diuretics or in combination with another diuretics (hydrochlorothiazide and antihypertensive). o Continuous use of potassium wasting diuretics require daily potassium supplements because the kidney excrete electrolytes and body water. o Supplements are not used if clients are taking potassium sparing – hyperkalemia. This increases diuresis (urination) without the loss of potassium. o They are generally weak diuretics and work by interfering with the sodium- potassium exchange in the distal convoluted tubule of the kidneys. o Example: spironolactone (Aldactone), triamterene (Dyrenium) V. POTASSIUM SPARING DIURETICS SPIRONOLACTONE Therapeutic Effects/ Uses: o For edema and hypertension. Mode of Action: o Inhibit the sodium potassium pump (potassium is retained, sodium is excreted).  V. POTASSIUM SPARING DIURETICS ASSESSMENT o Assess VS, weight, UO & serum electrolytes values for baseline levels. o Obtain history of drugs and herbs taken daily. DIAGNOSIS o Risk for Fluid Volume Deficit  V. POTASSIUM SPARING DIURETICS PLANNING o Client’s fluid retention and BP will decrease. o Client’s serum electrolytes remain within normal range. INTERVENTIONS o Serum potassium level should be monitored (risk for hyperkalemia) o Monitor UO, must increase. Report if UO is less than 30 ml/h or less than 600 ml/d o Monitor VS. o Observe for signs and symptoms of hyperkalemia (nausea, diarrhea, abdominal cramps, tachycardia, peaked narrow T wave). o Administer in the morning to prevent nocturia. o Avoid exposure to direct sunlight – photosensitive Parenteral Fluids and Electrolytes Body Fluids Fluids in the body that It is contained in within are necessary for the body in several chemical reactions and compartments which transport of necessary are separated by a semi- nutrients and minerals. permeable membrane. MAJOR COMPARTMENTS Area within the cell membrane. 65% of total body fluid volume is in the IC Intracellular Compartment compartment. The area in the body that is outside the cell. 35% of total body fluid volume is in the EC Extracellular Compartment compartment. MAJOR COMPARTMENTS 3. Interstitial Compartment (Tissues) - It is the space between the capillaries and the cells. - The Fluids within this compartment supports the surrounding tissue’s matrix integrity. - 25% of total body fluid volume is in this compartment.  OTHER FLUIDS AND MINOR COMPARTMENTS 4. Blood Plasma and Lymph - It represents 8% of total body fluid volume. 5. Transcellular Fluid - It represents 2% of TB fluid volume found within: eye humors, spinal fluid, synovial fluid, peritoneal, pericardial and pleural, and other body fluids.  Purpose and Uses Used to sustain clients who are unable to take substance orally. Replaces water, electrolytes and nutrients more rapidly than oral administration. It provides immediate access to vascular system for rapid delivery of specific solutions and medications without passing through gastrointestinal tract.  Crystalloid Solution General Aqueous solutions of mineral salts or other water-soluble molecules. Types of Colloidal Solution Parenteral Fluids Contains larger insoluble molecules, such as blood products, albumin derivatives and parenteral nutrition solutions. CRYSTALLOIDS  This type of intravenous fluid has the same concentration (Osmolality) as body fluids. Isotonic Most commonly used to hydrate extracellular compartments of the Solution body. It does not enter the cells as there are no osmotic force to shift the fluids. Isotonic Solution 0.9% Saline Solution (PNSS) Used in patients with Extracellular Deficits in: Low serum level of Sodium or Chloride; Metabolic Acid – Base Imbalances; and Used before and after the use of blood products. Isotonic Solution Ringer’s Lactate Solution (PLR) Used in patients with Extracellular Deficits in: Fluid loss secondary to burns, bleeding and dehydration from loss of bile and diarrhea.  Are more diluted solutions and have a lower osmolality that of the body fluids. Hypotonic Cause the movement of water into Solution the cell via osmosis. Should be administered slowly to prevent intracellular edema.  Hypotonic Solution 0.45% Normal Saline (Half Normal Saline) Treatment of hypertonic extracellular dehydration; and Hypovolemia. Hypotonic Solution 5% Dextrose in Water (D5W) Used in patients with Deficits in total body fluid volume Hypoglycemia.  Hypotonic Solution 5% Dextrose in Water (D5W) NOTE: It is isotonic at administration but within a short period of time, the body metabolized the dextrose component. Thus, tonicity of the fluid decreases becoming hypotonic in nature. Also, it is not used alone to expand extracellular fluid volume as dilution of electrolytes may occur. Hypertonic Solution - Are more - Causes movement of concentrated solution water from cells into and has a higher extracellular osmolality than body compartments by fluids. osmosis.  Hypertonic Solution 5% Dextrose in 0.9% Saline Solution (D5NSS) Extracellular fluid volume deficit in patients with: Low serum levels of Sodium and Chloride Metabolic Alkalosis  Hypertonic Solution 5% Dextrose in Lactated Ringer’s Solution (D5LR) Used in patients with Extracellular Deficits in: Low serum level of Sodium or Chloride; Metabolic Acid – Base Imbalances; Used before and after the use of blood products; and Glucose component for nutrient replacement. Colloids (Plasma Expanders)  It pulls fluids from interstitial spaces into intravascular compartment; Colloids (Plasma Ideally used to increase intravascular volume rapidly of Expanders) cases such as hemorrhage and severe hypovolemia; and Infusion of larger nutritional particles such as carbohydrates, proteins and Lipids. 1. Albumin Derivatives Example: Albuminex, Kedbumin (Albumin IV) It works by increasing plasma volume or levels of albumin in the blood by pulling fluid from interstitial spaces into intravascular space replacing blood loss from trauma. It helps maintain the osmotic pressure between the blood vessels and tissues  2. Blood Products A blood product is any therapeutic substance prepared from human blood. This includes whole blood; blood components; and plasma derivatives. 3. Total Parenteral Nutrition (TPN) Infusion method of feeding that bypasses the gastrointestinal tract. Fluids are given into a vein to provide most of the nutrients the body needs. The method is used when a person cannot or should not receive feedings or fluids by mouth. ELECTROLYTES Electrolytes These are minerals that carry an electric charge when they are dissolved in a liquid such as blood. The blood electrolytes—sodium, potassium, chloride, and bicarbonate. It helps regulate nerve & muscle function; and maintain acid-base balance and water balance.  Locations of Electrolytes in the Body Compartments Intracellular Potassium Fluid Electrolytes: Phosphorus Extracellular Sodium Fluid Electrolytes: Chloride Electrolytes Normal Serum (Blood/Intravascular) Levels Sodium 135 – 145 mEqs/L Potassium 3.5 – 5 mEqs/L Calcium 4.5 – 5.5 mEqs/L Phosphorus 1.7 – 2.6 mEqs/L Chloride 98 – 108 mEqs/L Magnesium 1.5 – 2.5 mEqs/L  Concentration of Na across Sodium Major Cation in Extracellular fluid and the cellular membrane plays and important part in spaces; and Neuromuscular Cellular Activity Potassium Major Cation in the intracellular fluid and spaces; and Critical to neuromuscular function because it plays an important role in action potential, nerve polarization and depolarization and excitability (especially in the myocardium). Chloride MOST CHLORIDE IN THE PLAYS A MAJOR ROLE IN BODY ARE SALTS FLUID BALANCE AND INGESTED AND ARE HYDRATION; AND ABSORBED IN THE BODY AS THE FOOD DIGEST.  Calcium Mineral necessary for Clotting Factor IV which controls bleeding; Has a role in cardiac muscle contraction and excitability; It is usually stored in the bones and teeth and is utilized with the help of a hormone called Calcitonin that is being regulated by the thyroid gland.  Magnesium Found primarily in the intracellular environment and is bound to adenosine triphosphate (ATP), the energy of the cell, which is important in the body’s metabolic functions. Phosphate Necessary to maintain acid base balance (through the Buffer System) The bicarbonate buffer system is an acid-base homeostatic mechanism involving the balance of carbonic acid and carbon dioxide (In the Lungs) and Bicarbonate (in the Kidneys) in order to maintain pH in the blood and duodenum, among other tissues, to support proper metabolic function.