Diuretics Flashcards
(40 cards)
Diuresis
Increased water loss
Diuretic drugs
-Increase urine output
-remove excess fluid
-First line drugs for (heart failure, hypertension)
-Acute edematous states
-Accelerate the rate of urine formation
How do diuretics control the rate of urine formation
-Mostly through excretion of Na+ and H2O
-Na+ and Cl- > control H2O > Control ECF volume > Part of BP control
The Nephron and what parts Na is absorbed
-Controls H2O movement (Follows Na)
-20-25% of all Na is absorbed in loop of Henle
-7% in distal tubules
-1-2% in collecting ducts
If H2O isn’t absorbed
gets excreted as urine
Diuretic Drugs
-Small blockade Na reabsorption can produce profound fluid loss
-Can produce
>Excess fluid loss
>Acid-base imbalances
>Alter electrolyte levels
Types of Diuretis
-Loop Diuretics
-Thiazide like diuretics
-Potassium-sparing diuretics
-Osmotic diuretics
-All block NaCl reabsorption
Loop Diuretics:
-Furosemide (Lasix)
-Bumetanide (Burinex)
-Ethacrynicacid (Edecrin)
Furosemide (Loop Diuretics): Mechanism of action
-Act in ascending loop of henle (inhibit Na+Cl transporter, secreted into nephron fluid)
-significant diuresis
-Decreased fluid volume causes (reduced edema, reduced venous return- reduced CO)
Furosemide (Loop Diuretics): indications
-Edema associated with heart failure, hepatic, or renal disease
-Control of hypertension
-Increase excretion of calcium in clients with hypercalcemia
Furosemide (Loop Diuretics): Adverse effects
-Excessive fluid loss (low Na, Cl)
-H2O dehydration
-Hypotension, thrombosis/embolism
-Potassium depletion (Hyperkalemia)
-Hyperuricemia (lead to gout)
-Hyperglycemia
What is important to watch for when taking diuretics
HypoKalemia
HypoKalemia Symptoms
-K below 3.5-5mmol/L
-Irregular heartbeat (potentially fatal dysrhythmias)
-Muscle weakness/lethargy
-Leg cramps
-GI Disturbances (constipation, nausea, vomiting, diarrhea)
Furosemide (Loop Diuretics): Interactions
-Patients using digitoxin need to be monitored for hypokalemia (can increase digoxin toxicity)
-Ototoxicity
-Increased levels of lithium (bipolar disorder)
-May decrease hypoglycemia effect of antidiabetic drugs = hyperglycemia
Thiazide Related Diuretics: Mechanism of action
-Inhibit reabsorption of Na and Cl ions
-Primarily in distal tubule
-different protein targets then loop diuretics
-less powerful then loop diuretics (low ceiling)
Furosemide (Loop Diuretics): cause
-excretion of H2O, Na,Cl
-reduce blood volume
Furosemide (Loop Diuretics): Drugs
-Hydrochlorothiazide
-Chlorthalidone
-Metolazone
Furosemide (Loop Diuretics): Indications
-Hypertension (first line treatment, single or combination therapy)
-Edematous States (adjunct agents in treatment of Heart Failure, hepatic cirrhosis)
Furosemide (Loop Diuretics): Adverse Effects
-Hypokalemia
-Hyperuricemia
-Hyperglycemia (inhibit insulin)
-Gentourinary system (Impotence)
Furosemide (Loop Diuretics): Indications
-Digoxin (increase risk of toxicity due to hypokalemia, same as loop)
-Antidiabetic drugs (reduces effect from diabetic drugs- can lead to hyperglycemia)
Potassium-Sparing Diuretics:
-Act of collecting tubules of nephron
-Only 1-2% of Na reabsorption
-Limited effectiveness when used on their own
Potassium-Sparing Diuretics: Spironolactone (Aldactone)
-Aldosterone receptor blockers
-Onset 24-48h
-Peak 2-3 days
Potassium-Sparing Diuretics: Na channel blockers
-Amiloride (Midamor)
-Triamterene (available only in combination with hydrochlorothiazide> Riva-zide)
Potassium-Sparing Diuretics: Mechanism of Action
-Antagonist at aldosterone receptors (block Na and H2O reabsorption usually induced by aldosterone)
-Reduces Na/K exchange (body retains K)
