Roach: Introductory Clinical Pharmacology

Introduction to Clinical Pharmacology Chapter 33 Diuretics Copyright 2018 Wolters Kluwer All Rights Reserved Edema Edema: accumulation of excess water in the body Edema (fluid retention) associated with HF, corticosteroid/estrogen therapy, and cirrhosis of the liver

Potassium-sparing diuretics Thiazides and related diuretics Copyright 2018 Wolters Kluwer All Rights Reserved Diuretics: Actions #1 Carbonic anhydrase inhibitors: such as acetazolamide (Diamox) and methazolamide Inhibit the enzyme carbonic anhydrase Result in excretion of sodium, potassium, bicarbonate, and water Used to treat glaucoma Decrease the production of aqueous humor in

the eye, which in turn decreases intraocular pressure Copyright 2018 Wolters Kluwer All Rights Reserved Diuretics: Actions #2 Loop diuretics: such as furosemide (Lasix) Increase the excretion of sodium and chloride Torsemide(Demadex): acts primarily in the ascending portion of the loop of Henle Bumetanide: acts primarily in the proximal tubule of the nephron

Copyright 2018 Wolters Kluwer All Rights Reserved Diuretics: Actions #3 Potassium-sparing diuretics: Triamterene, amiloride: depress the reabsorption of sodium in the kidney tubules Spironolactone: antagonizes the action of aldosterone Aldosterone: enhances the reabsorption of sodium in the distal convoluted tubules of the kidney Copyright 2018 Wolters Kluwer All Rights Reserved

Diuretics: Actions #4 Thiazides and related diuretics: such as chlorothiazide, hydrochlorothiazide, metolazone Inhibit reabsorption of sodium and chloride ions in the ascending portion of the loop of Henle and early distal tubule of nephron Osmotic diuretics: Such as isosorbide, mannitol, urea Increase the density of the filtrate in the glomerulus Mannitol given only IV (intravenously)

Copyright 2018 Wolters Kluwer All Rights Reserved Diuretics: Uses Used in the treatment of: Edema associated with congestive heart failure Hypertension Renal disease Cerebral edema Acute glaucoma and increased IOP Seizures and altitude sickness Copyright 2018 Wolters Kluwer All Rights Reserved

Diuretics: Adverse Reactions Neuromuscular reactions: dizziness, lightheadedness, headache, weakness, fatigue Cardiovascular reactions: orthostatic hypotension, electrolyte imbalances, glycosuria Gastrointestinal (GI) reactions: anorexia, nausea, vomiting Other reactions: hypokalemia, hyperkalemia, gynecomastia Copyright 2018 Wolters Kluwer All Rights Reserved Diuretics: Contraindications

Contraindicated in patients: With known hypersensitivity to the drugs, electrolyte imbalances, severe kidney or liver dysfunction, and anuria Mannitol: contraindicated in patients with active intracranial bleeding Potassium-sparing diuretics: contraindicated in patients with hyperkalemia; not recommended for children Copyright 2018 Wolters Kluwer All Rights Reserved Diuretics: Precautions

Used cautiously in patients with renal dysfunction; during pregnancy, lactation Thiazide and loop diuretics: Used cautiously in patients with liver disease, diabetes, systemic lupus erythematosus, or diarrhea Hold next dose in patients with renal compromise if BUN is elevated Question if giving with a sulfonamide due to possible cross sensitivity Monitor pulse rate and rhythm when taking digoxin due to possible cardiac arrhythmias Potassium-sparing diuretics: Used cautiously in patients with liver disease, diabetes, or

gout When diabetic taking loop diuretic monitor blood glucose Copyright 2018 Wolters Kluwer All Rights Reserved Diuretics: Interactions #1 Carbonic anhydrase inhibitors Interactant drug Primidone Effect of interaction Decreased effectiveness of primidone

Copyright 2018 Wolters Kluwer All Rights Reserved Diuretics: Interactions #2 Loop diuretics Interactant drug Digitalis Cisplatin, aminoglycosides Anticoagulants or thrombolytics Lithium Hydantoins (phenytoin) NSAIDs and salicylates Effect of interaction

Increased risk of arrhythmias Increased risk of ototoxicity Increased risk of bleeding Increased risk for lithium toxicity Decreased diuretic effectiveness Decreased diuretic effectiveness Copyright 2018 Wolters Kluwer All Rights Reserved Diuretics: Interactions #3 Potassium-sparing diuretics Interactant drug

Effect of interaction Angiotensin-converting enzyme (ACE) inhibitors or potassium supplements such as lisinopril Nonsteroidal antiinflammatory drugs (NSAIDs), salicylates, and anticoagulants Increased risk for hyperkalemia

Decreased diuretic effectiveness Copyright 2018 Wolters Kluwer All Rights Reserved Diuretics: Interactions #4 Thiazides and related diuretics Interactant drug Allopurinol Effect of interaction Increased risk for hypersensitivity to allopurinol

Nursing Process: Assessment #1 Preadministration assessment: Take vital signs and weigh the patient Review laboratory results; especially electrolytes such as potassium If patient has peripheral edema: inspect the involved areas and record in the patients chart the degree and extent of edema Review the patients chart for a description of the seizures and their frequency Copyright 2018 Wolters Kluwer All Rights Reserved

Nursing Process: Assessment #2 Ongoing assessment: Measure and record fluid intake and output Ensure diuretic given early in day (AM and lunch) Report to the primary health care provider any marked decrease in the fluid output Weigh the patient daily Assess for possible signs of hypokalemia which include anorexia, vomiting, nausea, depression, confusion, cardiac arrhythmias, impaired thought process, and/or drowsiness Assess for signs of hyponatremia such as cold, clammy skin, decreased skin turgor, confusion, hypotension,

irritability, tachycardia Copyright 2018 Wolters Kluwer All Rights Reserved Nursing Process: Diagnosis Impaired Urinary Elimination related to action of the diuretics causing increased frequency Risk for Deficient Fluid Volume related to excessive diuresis secondary to administration of a diuretic Risk for Injury related to lightheadedness, dizziness, or cardiac arrhythmias Copyright 2018 Wolters Kluwer All Rights Reserved

Nursing Process: Planning Expected outcomes: Optimal response to drug therapy Management of patient needs related to adverse drug reactions Correction of a fluid volume deficit Absence of injury Understanding of and compliance with the postdischarge drug regimen Copyright 2018 Wolters Kluwer All Rights Reserved Nursing Process: Implementation

#1 Promoting an optimal response to therapy Patient with edema: Weigh the patient; measure and record the fluid intake and output Assess the blood pressure, pulse, respiratory rate Examine areas of edema daily and record findings in the patients chart Copyright 2018 Wolters Kluwer All Rights Reserved Nursing Process: Implementation

#2 Promoting an optimal response to therapy (cont.) Patient with hypertension: Monitor blood pressure, pulse, respiratory rate before administration of the drug Copyright 2018 Wolters Kluwer All Rights Reserved Nursing Process: Implementation #3 Promoting an optimal response to therapy (cont.) Patient with acute glaucoma: Evaluate the patients response to drug therapy

every 2 hours Assist the patient with ambulatory and self-care activities Copyright 2018 Wolters Kluwer All Rights Reserved Nursing Process: Implementation #4 Promoting an optimal response to therapy (cont.) Patient with seizure activity: Assess the patient at frequent intervals for the occurrence of seizures Record a description of the seizure in the patients

chart, including time of onset and duration Copyright 2018 Wolters Kluwer All Rights Reserved Nursing Process: Implementation #5 Promoting an optimal response to therapy (cont.) Patient with increased intracranial pressure Monitor the urine output, blood pressure, pulse, and respiratory rate Perform neurologic assessments at specific time intervals

Monitor for signs and symptoms indicating decrease in intracranial pressure Monitor for syncope; headache, nausea, vomiting, and fluid and electrolyte imbalance Copyright 2018 Wolters Kluwer All Rights Reserved Nursing Process: Implementation #6 Promoting an optimal response to therapy (cont.) Patient with renal compromise: Monitor renal function periodically Monitor serum uric acid concentrations and serum

glucose concentration periodically Monitor for any joint pain or discomfort Copyright 2018 Wolters Kluwer All Rights Reserved Nursing Process: Implementation #7 Promoting an optimal response to therapy (cont.) Patient at risk for hypokalemia: Monitor serum potassium levels frequently Treatment for hyperkalemia: administer IV bicarbonate or oral or parenteral glucose with rapidacting insulin

Copyright 2018 Wolters Kluwer All Rights Reserved Nursing Process: Implementation #8 Monitoring and managing patient needs Impaired urinary elimination: Explain the purpose and effects of the drug to reduce anxiety Administer the drug early in the day Make sure that patient on bed rest has a call light and a bedpan or urinal within easy reach

Copyright 2018 Wolters Kluwer All Rights Reserved Nursing Process: Implementation #9 Monitoring and managing patient needs (cont.) Risk for deficient fluid volume: Encourage patients to eat and drink all food and fluids served at mealtime Monitor fluid intake and output Assess for signs and symptoms of electrolyte imbalance

Copyright 2018 Wolters Kluwer All Rights Reserved Nursing Process: Implementation #10 Monitoring and managing patient needs (cont.) Risk for injury: Frequently monitor pulse rate and rhythm Assist patients who are dizzy but allowed out of bed with ambulatory activities Copyright 2018 Wolters Kluwer All Rights Reserved Nursing Process: Implementation

#11 Educating the patient and family Explain the importance of taking the drug at prescribed time intervals and as directed Advise about the importance of completing the entire course of treatment Emphasize the importance of taking the drug with food or milk Copyright 2018 Wolters Kluwer All Rights Reserved Nursing Process: Implementation #12

Educating the patient and family (cont.) Do not reduce fluid intake to reduce the need to urinate Instruct patient to avoid alcohol and nonprescription drugs Emphasize observing caution while driving or performing hazardous tasks Explain necessary interventions if dizziness or weakness occurs Copyright 2018 Wolters Kluwer All Rights Reserved Nursing Process: Implementation

#13 Educating the patient and family (cont.) Explain the importance of avoiding exposure to sunlight or ultraviolet light Explain to patients with diabetes mellitus and who take loop or thiazide diuretics to contact health care provider if increase in blood glucose level; avoid OTC drugs for appetite suppression and cold symptoms due to increase in blood pressure Copyright 2018 Wolters Kluwer All Rights Reserved Nursing Process: Implementation

#14 Educating the patient and family (cont.) For patients taking potassium-sparing diuretics: emphasize the importance of avoiding foods high in potassium and use of salt substitutes containing potassium Monitor potassium levels; sodium and other electrolyte levels For patients taking thiazide diuretics: explain the necessity of contacting the primary health care provider if sudden joint pain occurs Copyright 2018 Wolters Kluwer All Rights Reserved

Nursing Process: Implementation #15 Educating the patient and family (cont.) For patients taking carbonic anhydrase inhibitors: explain the necessity of contacting the primary health care provider immediately if eye pain is not relieved or increased Copyright 2018 Wolters Kluwer All Rights Reserved Nursing Process: Evaluation #1 Therapeutic effect is achieved

Adverse reactions are identified, reported, and managed successfully Fluid volume problems are corrected No injury is evident Copyright 2018 Wolters Kluwer All Rights Reserved Nursing Process: Evaluation #2 Patient verbalizes the importance of complying with the prescribed treatment regimen Patient and family demonstrate an understanding of the drug regimen Need to also ensure that patient is aware of the nutrition

needs and awareness that can influence electrolytes when on diuretics Also need to be aware of the signs and symptoms of hypokalemia, hyperkalemia, hyponatremia, hypernatremia to name a few Need to be aware of signs and symptoms of fluid and electrolyte imbalances Copyright 2018 Wolters Kluwer All Rights Reserved Question #1 Is the following question true or false? Excessive fluid is involved in many conditions such as HF, endocrine disturbances, and kidney and liver

diseases. Copyright 2018 Wolters Kluwer All Rights Reserved Answer to Question #1 True Excessive fluid is involved in many conditions such as HF, endocrine disturbances, and kidney and liver diseases. Copyright 2018 Wolters Kluwer All Rights Reserved Question #2

Is the following question true or false? Pressure of fluid in the blood vessels contributes to hypotension. Copyright 2018 Wolters Kluwer All Rights Reserved Answer to Question #2 False Pressure of fluid in the blood vessels contributes to hypertension. Copyright 2018 Wolters Kluwer All Rights Reserved

Question #3 Is the following statement true or false? Diuretics are drugs that reduce body fluid by increasing production of urine by altering the excretion or reabsorption of electrolytes in the kidney. Copyright 2018 Wolters Kluwer All Rights Reserved Answer to Question #3 True Diuretics are drugs that reduce body fluid by increasing production of urine by altering the excretion or reabsorption of electrolytes in the kidney.

Roach: Introductory Clinical Pharmacology

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