1. Drugs Used for Diuresis
Chapter 29
Drugs Used for Diuresis
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2. Chapter 29
Lesson 29.1
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3. Objectives Identify the action of diuretics
Describe the goal of administering diuretics to treat hypertension, heart failure, or increased intraocular pressure or before vascular surgery in the brain
Identify the effects of diuretics on blood pressure, electrolytes, and diabetic or prediabetic patients
Review possible underlying pathologic conditions that may contribute to the development of excess fluid volume in the body
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4. Diuretics
Used to increase flow of urine to reduce excess water in the body
Primarily used to treat heart failure, hypertension
Other uses: liver disease, renal disease, cerebral edema, increased intraocular pressure, treat hypercalcemia
Therapeutic outcomes: reduce edema, improve symptoms of excess fluid
After lifestyle modifications, diuretics (often in addition to other antihypertensives) may be used as primary agents to treat hypertension.
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5. Pathologic Conditions Contributing to Excess Fluid
Heart failure
Edema, adventitious lung sounds, dyspnea, change in mental status
Liver disease
Jaundice, ascites, disorientation, history of alcohol dependence, overdose of OTC medications
Adverse outcomes if diuretics not given: renal failure, pulmonary congestion, edema, hypertension, stroke, death
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6. Sites of Action in the Nephron
Diuretics act on the kidneys to decrease reabsorption of sodium, chloride, and water.
The distal tubules is the site of action for thiazide and potassium-sparing drugs.
The loop of Henle is the site of action for loop-diuretics.
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7. Chapter 29
Lesson 29.2
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8. Objectives Cite nursing assessments used to evaluate renal function
Cite nursing assessments used to evaluate a patient’s state of hydration
State which electrolytes may be altered by diuretic therapy
Review the signs and symptoms of electrolyte imbalance and normal laboratory values of potassium, sodium, and chloride
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9. Objectives (cont’d)
Explain the rationale for administering diuretics cautiously to older adults and individuals with impaired renal function, cirrhosis of the liver, or diabetes mellitus
Develop objectives for patient education for patients taking loop, thiazide, and potassium-sparing diuretics
List adverse effects that can be anticipated whenever a diuretic is administered
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10. Objectives (cont’d)
State the nursing assessments needed to monitor therapeutic response or the development of common or serious adverse effects from diuretic therapy
Cite alterations in diet that may be prescribed concurrently with loop, thiazide, or potassium-sparing diuretic therapy
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11. Renal Function: Assessment
History of related causative disorders/factors
History of current symptoms
Pattern of urination
Medication history
Hydration status
Electrolyte imbalance
Often subtle changes, such as in mental status, muscle strength/cramps, tremors, nausea, general appearance
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12. Nursing Assessment for Hydration Status
Evaluate for dehydration: skin turgor, oral mucous membranes
Monitor laboratory values for changes
Evaluate location of edema, signs of reduction
Obtain daily weights
Measure intake and output
Common sites to check skin turgor are over the sternum, on the forehead and on the forearm.
Weight gain that alerts the patient or nurse to increasing edema is generally 2 lb per day.
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13. Electrolyte Imbalance
Susceptible people: history of renal or cardiac disease, hormonal disorders, massive trauma or burns
Assess mental status, muscle strength and cramps, tremors, nausea, general appearance
Serum potassium < 3.5 mEq/L (hypokalemia), > 5.5 mEq/L (hyperkalemia)
Serum sodium < 135 mEq/L (hyponatremia), > 145 mEq/L (hypernatremia)
Potassium depletion can cause weakness of cardiovascular, respiratory, digestive, and skeletal muscles.
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14. Patient Education Considerations
Accurate measurement of fluid intake and output
Purpose of diuresis
Medication considerations
Nutrition
Health maintenance
Written record/patient self-assessment form
The prescriber orders furosemide 80 mg for a patient who had been retaining extra fluid after surgery. The nurse notes the following: BP of 142/88 (lying) and 108/60 (sitting); daily weight of 154 lb, a 1-lb drop from day before; serum potassium of 2.8 mEq/L. Should the nurse administer the furosemide? (The nurse should report the data to the charge nurse or the physician. The patient’s drop in weight is too much for 1 day; orthostatic blood pressure indicates volume depletion; potassium level shows diuresis is occurring too rapidly.)
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15. Drug Class: Carbonic Anhydrase Inhibitor
Drug: acetazolamide (Diamox)
Actions
Weak diuretic; inhibits the enzyme carbonic anhydrase in kidney, brain, eye
Uses
Reduces intraocular pressure with glaucoma; reduce seizure activity with certain types of epilepsy
See Chapters 19 and 43 for further discussion
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16. Drug Class: Sulfonamide-Type Loop Diuretics
Actions
Inhibit sodium and chloride reabsorption in ascending limb of the loop of Henle
Uses
Treat conditions such as edema resulting from heart failure, cirrhosis of the liver, renal disease
Common adverse effects
Oral irritation, dry mouth; orthostatic hypotension
Serious adverse effects
Gastric irritation, abdominal pain; electrolyte imbalance, dehydration; hyperuricemia; hyperglycemia; hives, pruritus, rash
Drugs: bumetanide (Bumex), furosemide (Lasix), ethacrynic acid (Edecrin), torsemide (Demadex).
Furosemide is also used to treat hypertension.
Ethacrynic acid is more effective than other loop diuretics in patients with significant renal failure.
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17. Drug Class: Thiazide Diuretics
Actions
Block reabsorption of sodium and chloride ions from the tubule
Uses
Treat edema associated with heart failure, renal disease, hepatic disease, pregnancy, obesity, premenstrual syndrome
Common adverse effects
Orthostatic hypotension
Serious adverse effects
Gastric irritation, electrolyte imbalance, hyperuricemia, hyperglycemia
For specific drugs, see Tables 29-2 and 29-3.
Used for more long-term management of heart failure and hypertension.
Not strong diuretics; have a slow onset of action.
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18. Drug Class: Potassium-Sparing Diuretics
Drugs: amiloride (Midamor), spironolactone (Aldactone), triamterene (Dyrenium)
Actions
Induce retention of potassium; excrete sodium at the distal renal tubules
Uses
In combination with other diuretics to treat hypertension or heart failure, prevent hypokalemia
Common and serious adverse effects
Nausea, vomiting, anorexia, flatulence, headache, electrolyte imbalance, dehydration
Instruct patients not to use salt substitutes, which are high in potassium, to prevent hyperkalemia.
Contraindicated in patients with renal impairment because of high risk of hyperkalemia.
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19. Drug Class: Combination Diuretic Products
Drugs
Spironolactone/hydrochlorothiazide (Aldactazide)
Triamterene/hydrochlorothiazide (Dyazide, Maxzide)
Amiloride/hydrochlorothiazide (Moduretic)
Actions
Potassium-sparing diuretics / thiazide diuretics
Uses
Promote diuresis while maintaining normal potassium levels
Common adverse effects
Hyperkalemia, hyponatremia
For specific drugs, see Table 29-4.
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