Diuretics Flashcards
Intracellular Fluid
-Inside the cell
-Largest compartment and holds 2/3 of the total body water
Extracellular fluid
-Outside of the cell
-1/3 of the total body water.
-Divided into vascular compartments (blood vessels) and the interstitial space (gaps between the cells)
Abnormal fluid loss
-Vomiting
-Diarrhea
-Hemorrhage
Signs and symptoms of fluid loss
-Low blood pressure
-Weak
-Dry skin
-Treatment- Give fluids
Abnormal retention of fluids
-Congestive heart failure
-Kidney failure
Signs and Symptoms of fluid retention
-Crackles in lungs
-Dyspnea (difficulty breathing)
-Edema
Nursing interventions
-Assess patient
-Daily weights
-Monitor intake and output
-IV fluids
3 basic functions of diuretics
-Cleansing of extracellular fluid and maintenance of ECF volume and composition.
-Maintenance of acid-base balance.
-Excretion of metabolic wastes and foreign substances.
Aldosterone
-Principal mineralocorticoid of the adrenal cortex, stimulates reabsorption of sodium from the distal nephron.
-At the same time, aldosterone causes potassium to be secreted.
Two major applications of diuretics
-Treatment of hypertension- helps to regulate fluid and blood pressure.
-Mobilization of edematous fluid to prevent renal failure.
Diuretics mechanism of action
-Blockade of sodium and chloride reabsorption.
Adverse effects of diuretics- too much fluid is pulled off
-Hypovolemia
-Acid-base imbalance
-Electrolyte imbalance
Loop Diuretics
Mechanism of action
-Acts on ascending loop of henle to block reabsorption of sodium and chloride.
Furosemide (Lasix)
-Most prescribed loop diuretic
-Rapid onset (PO 60 min, IV 5 min)
Therapeutic use of furosemide
-Pulmonary edema from CHF
-Edema of cardiac, hepatic or renal origin that has been unresponsive to less efficacious diuretics
-Hypertension that cannot be controlled with other diuretics
Adverse Effects of Furosemide
-Hyponatremia, hypochloremia, and dehydration.
-If dehydration occurs, hold
furosemide
-Hypotension due to loss of volume and relaxation of venous smooth muscle; which reduces venous return to the heart.
Hypokalemia- potassium is lost through increased secretion in the distal nephron.
-Low potassium can cause cardiac dysrhythmias.
-Ototoxicity- deafness is transient.
-Hyperglycemia- can interfere with glucose metabolism.
-Hyperuricemia- Gout
-Don’t give during pregnancy.
Drug interactions of Furosemide
-Digoxin- In the presence of low potassium, the risk of digoxin-induced toxicity (ventricular dysrhythmias) is increased. Loop diuretics promote potassium loss.
-Ototoxic drugs
-Potassium-sparing diuretics
-Lithium
-Antihypertensive drugs
-NSAIDS
Preparations, dosage, and administration of Furosemide
-Oral
-Parenteral
-Given IV, administer slowly over 1-2 min
-If pushed fast it can cause hearing loss.
Thiazides
-Used for newly diagnosed pt. with hypertension.
-Also know as benzothiadiazides
-Diuresis is considerably lower than that produced by loops.
Thiazide mechanism of action
-Promotes urine production by blocking the reabsorption of sodium and chloride in the early segment of the distal convoluted tubule.
-Because only 10% of filtered sodium and chloride is normally absorbed at the site where thiazides act, the maximum urine flow these drugs can produce is lower than with loops.
Hydrochlorothiazide (Hydrodiuril)
-Diuresis begins about 2 hours after oral administration.
-Effects peak within 4 to 6 hours
Therapeutic uses of Hydrochlorothiazide
-Hypertension
-Edema
-Diabetes insipidus
Adverse effects of Hydrochlorothiazide
-Hyponatremia
-Hypochloremia
-Dehydration
-Hypokalemia
-Hyperglycemia
-Hyperuricemia
-Impact on lipids, calcium and magnesium.
-Can be used during pregnancy
Hydrochlorothiazide drug interactions
-Digoxin
-Augments effects of hypertensive medication
-Reduction of renal excretion of lithium (leading to accumulation)
-NSAIDs can blunt diuretic effects
-Can be combined with ototoxic agents without increased risk of hearing loss.
Potassium-sparing diuretics
-Modest increase in urine production
-Decrease in potassium excretion
Two groups of potassium-sparing diuretics
-Aldosterone Antagonist- Spironolactone
-Non-aldosterone antagonist- Triamterene and Amiloride
Spironolactone Mechanism of Action
-Blocks aldosterone in the distal nephron
-Retention of potassium
-Increased secretion of sodium
-Diuresis for spironolactone is scant because most of the filtered sodium load has already been reabsorbed by the time the filtrate reaches the distal nephron.
Therapeutic Uses of Spironolactone
-Hypertension
-Edematous states
-Heart failure (decreases mortality in severe failure)
-Primary hyperaldosteronism
-Premenstrual syndrome
-Polycystic ovary syndrome
-Acne in young women
Adverse Effects of Spironolactone
-Hyperkalemia
-Benign and malignant tumors
-Endocrine effects
-Draw blood to know potassium levels
Drug Interactions
-Thiazide and loop diuretics
-Agents that raise potassium levels
Osmotic Diuretic
Mannitol (Osmitrol)
-Promotes diuresis by creating osmotic force within lumen of the nephron.
-Mannitol has no significant effect on the excretion of potassium and other electrolytes.
Mannitol (Osmitrol)
-Drug must be given parentally!
-Given IV
-Does not diffuse across the GI epithelium and cannot be transported by the reuptake systems that absorb dietary sugars.
-Diuresis begins in 30 to 60 min and persists 6 to 8 hours.
Therapeutic Uses of Mannitol (Osmitrol)
-Prophylaxis of renal failure
-Reduction of intracranial pressure
-Reduction of intraocular pressure
Adverse Effects of Mannitol (Osmitrol)
-Edema
-Headache
-Nausea and vomiting
-fluid and electrolyte imbalance
