Term
|
Definition
| Diuretics are drugs that increase the output of urine |
|
|
Term
| Name two major applications for diuretics |
|
Definition
Treatment of hypertension
mobilization of edematous fluid (associated with heart failure, cirrhosis, and kidney disease) |
|
|
Term
| Name the four functionally distinct regions of the nephron. |
|
Definition
Glomerulus The proximal convoluted tubule The loop of Henle The distal convoluted |
|
|
Term
| Three basic renal processes |
|
Definition
Filtration - occurs in glomerulus; 1st step of urine formation Reabsorption- Active tubular secretion |
|
|
Term
| What is the basic mechanism of action that most diuretics share? |
|
Definition
| Blockage of sodium and chloride reabsorption |
|
|
Term
What does the blocking of the reabsorption of sodium and chloride create and cause? |
|
Definition
Create osmotic pressure within the nephron that prevents the passive reabsorption of water |
|
|
Term
What is the increase in urine flow that a diuretic produces directly related to? |
|
Definition
| The amount of sodium chloride reabsorption that it blocks |
|
|
Term
What drugs have the opportunity to block the greatest amount of solute reabsorption?
Therefore what is produced? |
|
Definition
Drugs whose site of action is early in the nephron
Diuresis |
|
|
Term
| Why do agents that act at distal sites produce relatively scant diuresis? |
|
Definition
Diuretics that act at distal sites have very little reabsorption available to block. |
|
|
Term
| Name the three adverse effects that result because diuretics must compromise the normal operation of the kidney in order to promote excretion of water. |
|
Definition
Hypovolemia (from excessive fluid loss)
Acid-base imbalance
Disturbance of electrolyte levels |
|
|
Term
| Name the four major categories of diuretic drugs |
|
Definition
1. High-ceiling (loop) diuretics (.furosemide)
2. Thiazide diuretics (Hydrochlorothiazide 3. Osmotic diuretics ( Mannitol)
4. Potassium-spareing diuretics |
|
|
Term
How effective are high-ceiling diuretics? What are they also known as? Why?
|
|
Definition
Most effective diuretics available Because their site of action is in the loop of Henle, the high-ceiling agents are also known as loop diuretics
|
|
|
Term
| Write the brand name of furosemide? |
|
Definition
|
|
Term
What is the mechanism of action of furosemide? How significant is the diuresis produced?
|
|
Definition
Furosemide acts in the thick segment of the ascending limb of Henle’s loop to block reabsorption of sodium chloride
this can produce profound diuresis |
|
|
Term
| Following the administration of furosemide how soon can diuresis be expected to begin… o given orally? o given by IV? |
|
Definition
given orally? 60 minutes and persist for 8 hours
given by IV? Within 5 minutes and last for 2 hours |
|
|
Term
| When is intravenous diuretic therapy used? |
|
Definition
| In critical situations (pulmonary edema) that demand immediate mobilization of fluid |
|
|
Term
| Name three examples of conditions that justify the use of a powerful diuretic such as furosemide? |
|
Definition
1. Pulmonary edema associated with congestive heart failure (CHF) 2. Edema of hepatic, cardiac, or renal origin that has been unresponsive to less efficacious diuretics 3. Hypertension that cannot be controlled with other diuretics |
|
|
Term
| Name the four most notable side effects of high-ceiling (loop) diuretics |
|
Definition
Hyponatermia,
Hypochloremia,
dehydration,
ototoxicity Hypotension, hypokalemia |
|
|
Term
Describe four signs that may indicate a patient receiving a diuretic is becoming dehydrated
|
|
Definition
Dry mouth, unusual thirst, orliguria (scanty urine output) excessive loss of weight |
|
|
Term
| Give the two reasons furosemide can cause a substantial drop in blood pressure. |
|
Definition
| Loss of volume and Relaxation of venous smooth muscle, which reduces venous return to the heart |
|
|
Term
| Describe three signs that a patient with hypotension might exhibit |
|
Definition
| Dizziness, lightheadedness, fainting |
|
|
Term
| Identify two precautions that should be included in discharge teaching for a patient prescribed a powerful diuretic. |
|
Definition
Outpatients should be taught to monitor their blood pressure and instructed to notify the physician if it drops substantially. Also, patients should be informed about symptoms of postural hypotension (dizziness, lightheadedness) and advised to sit or lie down if these occur.
Get up slowly, take pulse and pressure |
|
|
Term
| v At what level of serum potassium may fatal dysrhythmias result? |
|
Definition
| If serum potassium falls below 3.5 mEq/L, fatal dysrhythmias may result |
|
|
Term
| v Due to drug interaction, when is the loss of potassium of special concern? |
|
Definition
| Loss of potassium is or special concern for patients taking digoxin, a drug used for heart failure |
|
|
Term
| v Name six examples of potassium rich foods |
|
Definition
| Dried fruits, nuts, spinach, citrus fruits, potatoes, bananas |
|
|
Term
Is the hearing loss that may result from furosemide permanent?
Can hearing loss be permanent with other loop diuretics?
Does ototoxicity occur with diuretics in other categories? |
|
Definition
With furosemide, deafness is transient (temporary)
Yes (ex. Ethacrynic)
Diuretics in other classes are not ototoxic |
|
|
Term
| Why is the risk of ventricular dysrhythmias greatly increased with patients taking both digoxin and loop diuretics? |
|
Definition
| Since high-ceiling diuretics promote potassium loss, use of these drugs in combination with digoxin can increase the risk of dysrhythmias |
|
|
Term
| What increases the risk of furosemide induced hearing loss? |
|
Definition
Increased by concurrent use of other ototoxic drugs -especially
anminoglycoside antibiotics |
|
|
Term
| Name a class of over-the-counter drugs that can decrease the effects of furosemide. |
|
Definition
|
|
Term
| What time of day should be avoided when scheduling administration of a loop diuretic? Why? |
|
Definition
Late in the day, because administration late in the day produces nocturia and should be avoided
|
|
|
Term
| What is the brand name of bumetanide, another high ceiling loop diuretic? |
|
Definition
|
|
Term
How does the onset of this drug compare with furosemide?
o Bumex oral o Bumex IV |
|
Definition
Bumex Oral 30-60 min Bumex IV within a few minutes
Furosemide (Lasix) oral onset within 60 min Furosemide (Lasix) IV onset is within 5 min |
|
|
Term
| Although very similar in many properties with furosemide, is bumetanide used for hypertension? |
|
Definition
| No, only torsemide (Demadex) |
|
|
Term
v Although thiazide diuretics have similar effects to loop diuretics what is the principle difference?
|
|
Definition
| Is that the maximum dieresis produced by the thiazides is considerably lower than the maximum dieresis produced by the high-ceiling drugs |
|
|
Term
What is hydrochlorothiazide commonly used for, making it one of the most widely used drugs?
|
|
Definition
|
|
Term
| How does hydrochlorothiazide promote urine production? |
|
Definition
| By blocking the reabsorption of sodium and chloride in the early segment of the distal convoluted tublue |
|
|
Term
| Why is the maximum urine flow thiazides can produce lower than high-ceiling drugs? |
|
Definition
| Since only 10% of filtered sodium and chloride is normally reabsorbed at the site where thiazides act, the maximum urine flow these drugs can produce is lower than with the high-ceiling drugs |
|
|
Term
| v Why are thiazides not used to promote fluid loss in patients with severe renal impairment? |
|
Definition
The ability of thiazides to promote dieresis is dependent on adequate kidney function. These drugs are ineffective when glomerular filtration rate is low (less than 15 to 20 m:/min) |
|
|
Term
| When does diuresis normally begin following a thiazide diuretic? |
|
Definition
Dieresis begins about 2 hours after oral administration.
Effects peak within 4 to 6 hours, and may persist up to 12 hours??? |
|
|
Term
| What is the primary indication for hydrochlorothiazide? |
|
Definition
| Hypertension, a condition for which thiazides are often drugs of first choice |
|
|
Term
| Are thiazides used to treat edema? |
|
Definition
| Thiazides are preferred drugs for mobilizing edema |
|
|
Term
| How does the side effects of thiazide diuretics compare with high-ceiling (loop) diuretics? |
|
Definition
With the exception that thiazides lack ototoxic actions, the adverse effects of the thiazides and loop diuretics are nearly identical |
|
|
Term
| What impact do thiazides have on sodium, chloride, and water compared to loop diuretics. |
|
Definition
Since the dieresis produced by thiazides is moderate, these drugs have a smaller impact on soduium, chloride, and water than do the loop diuretics
|
|
|
Term
| Do thiazides cause hypokalemia? |
|
Definition
| Like the high-ceiling diuretics, the thiazides can cause hypokalemia from excessive potassium excretion |
|
|
Term
| Can thiazides be used to treat the edema of pregnancy? |
|
Definition
| It should not be used routinely during pregnancy. Edema of pregnancy is not an indication for diuretic therapy, except when unusually severe |
|
|
Term
Do thiazides also lead to any potential interaction with digoxin? Why or why not?
|
|
Definition
| By promoting potassium loss, thiazides can increase the risk of toxicity from digoxin. |
|
|
Term
Name two potentially useful responses to potassium sparing diuretics
|
|
Definition
First, they produce a modest increase in urine production
Second, they produce a substantial decrease in potassium excretion
|
|
|
Term
| v For what purpose are potassium sparing diuretics used with great regularity? |
|
Definition
Because of their marked ability to decrease potassium excretion,
these drugs are used with great regularity to counteract potassium loss caused by thiazide and loop diuretics |
|
|
Term
| v What is the brand name of spironolactone? |
|
Definition
|
|
Term
| What is the mechanism of action of spironolactone? |
|
Definition
Blocks the action of aldosterone in the distal nephronRetention of potassium and increased excretion of sodium |
|
|
Term
| v How long does it take for the onset of spironolactone? |
|
Definition
|
|
Term
| What is the most notable adverse effect of spironolactone? |
|
Definition
Hyperkalemia
(a condition that can produce fatal dysrhythmias) |
|
|
Term
| At what level of serum potassium is the increase a serious concern? |
|
Definition
| If it rises aboce 5 mEq/L, or if signs of hyperkalemia develop (abnormal cardiac rhythm), spironolactione should be discontinued and potassium intake restricted |
|
|
Term
| What physical assessment finding might indicate hyperkalemia? |
|
Definition
| abnormal cardiac rhythm??? |
|
|
Term
Because of the risk of hyperkalemia, what should spironolactone never be combined with?
|
|
Definition
Potassium supplements, salt substitutes
(which contain potassium chloride), or with another potassium-sparing diuretic |
|
|
Term
| Why does triamterene (Dyrenium) act so much more quickly then spironolactone? |
|
Definition
| Because it inhibits ion transport directly, triamterene acts much more quickly than spironolactone |
|
|
Term
Instruct pt’s using twice-a-day dosing to take their mediation at (to minimize nocturia) |
|
Definition
|
|
Term
| Teach pt’s to monitor their BP and instruct them to notify the physician if it drops substantially Inform pt’s about dizziness, lightheadedness |
|
Definition
|
|
Term
Teach pt’s the signs and symptoms of hypokalemia (irregular heartbeat, muscle weakness, cramping, flaccid paralysis, leg discomfort, extreme thirst, confusion), and stress the importance of showing up for |
|
Definition
|
|
