Diuretics

Question 1

Diuretic uses

Answer 1

Increases water loss (urine output)
Remove excess fluid

First line for:
heart failure
hypertension

Question 2

How do diuretics increase urine output?

Answer 2

most by excretion of sodium and water

Where sodium goes, water will follow

Question 3

Loop Diuretics
Mechanism
Considerations
Drug name

Answer 3

Act in ascending loop of henle
Inhibits sodium and chloride transporter

Significant diuresis
“High ceiling diuretics”

Decreased fluid causes: reduced edema and reduced venous return

DRUG: Furosemide (Lasix)
Indications: Edema from heart failure or hepatic or renal disease. Hypertension. Renal excretion of calcium in patients with hypercalcemia

Question 4

DRUG: Furosemide (Loop Diuretic) Adverse effects and Interactions

Answer 4

Excessive fluid loss
Low Na, Cl
Low water (dehydration): hypotension, thrombosis/embolism
potassium depletion = hypokalemia
Hyperuricemia (gout)
hyperglycemia

Interactions:
•Patients using digoxin need to be monitored for hypokalemia

•Ototoxicity with aminoglycosides
•Increases lithium levels
•May decrease hypoglycemic effect of insulin =hyperglycemia

Question 5

Thiazide Diuretics
Mechanism
Considerations
Drug name

Answer 5

•Action in distal tubule
•Inhibit reabsorption of Na, Cl, results in excretion of water, sodium, chloride
•Different protein target to loop diuretics
•Reduced blood volume

•Less powerful than loop diuretics - “low ceiling”

DRUG: Hydrochlorothiazide

Question 6

DRUG: Hydrochlorothiazide (thiazide diuretic) Adverse effects and interactions

Answer 6

Thiazide
Taken PO
First line Tx for hypertension

Adverse effects:
Hypokalemia
Hyperuricemia
Hyperglycemia
Impotence

Interactions: Digoxin. Increased risk of toxicity (hypokalemia)

Antidiabetic drugs. Reduces effect of diabetic drugs, can lead to hyperglycemia

Question 7

Potassium-Sparing Diuretics
mechanisms
considerations
drug name

Answer 7

Act on collecting tubules of nephron

Na channel blockers / aldosterone receptor blockers

Only 1-2% Na reabsorption
Therefore, limited effectiveness on own.

DRUG: Spironolactone (Aldactone)
Aldosterone receptor blocker
(Aldosterone causes us to retain salt and water)

Question 8

DRUG: Spironolactone (potassium sparing diuretic) Adverse effects and interactions

Answer 8

Spironolactone (Aldactone)
Onset 24-48 hrs
Peak 2-3 days

Agonist at aldosterone receptors (block’s reabsorption of water and sodium)

Reduces sodium-potassium exchange
“K-sparing”

Indications:
Edema, hypertension, heart failure, hyperaldosteronism, reversing potassium loss caused by potassium-losing drugs (combo therapy)

Contraindications:
Hyperkalemia

Adverse effects:
Hyperkalemia, sex hormone-like effects

Interactions:
ACE Inhibitors

Question 9

Patients taking diuretics along with a digoxin should be taught to monitor for

Answer 9

Digoxin toxicity

Fatigue, GI problems, change in heart rate/rhythm, anorexia, visual disturbances

Question 10

Diabetic pts taking which diuretics should monitor blood glucose and watch for elevated glucose?

Answer 10

Loop diuretics and Thiazide diuretics.

They can inhibit the glucose-lowering effects of diabetes medicine