Diuretics Flashcards
Where is the site of action of :
Loop diuretics
Thiazide diuretics
Carbonic anhydrase inhibitors
Potassium sparing diuretics
Ascending loop of henle
Distal and connecting tubules
Proximal tubule
Collecting tubule
What are the main actions of diuretics
1-Inhibiting sodium reabsorption and enhancing sodium and water in urine(loop)
2_ inhibiting sodium reabsorption and chloride(thiazide)
3-blocking the exchange of sodium with potassium resulting in excretion od sodium but little loss of potassium(potassium sparing diuretic)
T or F
Loop diuretics are the most used diuretics
False
They are the most effective leading to excretion of 20% of salt and water (normal reabsorption of the transporter)
Mode of action of loop diuretics
Inhibit sodium potassium chloride cotransporter in the ascending loop
What ions will be excreted more under the effect of loop diuretics
Na+
K+
Cl-
Ca2+ (ad l Na+ taarebn)
Whats the other mode of action of loop diuretics
Induce renal synthesis of prostaglandins which contribute to increase in renal blood flow and redistribution of renal cortical blood flow
List the names of loop diuretics
Derivative of?
MOA
Side effects if present
Bumetanide-furosemide: sulfonamide derivative, orally or IV
Ethacrynic acid: not sulfonamide derivative (when patient is allergic to sulfonamide) less used because of ototoxicity
For what loop diuretics are used for:
1-
2-
3-
Pulmonary edema (vasodilation when administered Iv)
Chronic congestive heart failure( to minimize venous and pulmonary congestion)
Hypertension
Thiazide diuretics:
Low or high ceiling diuretic?
Mode of action
Location of action
Efficacy?
Low (high for loop diuretics)
Inhibit Na+ and Cl- reabsorption from the transporter at the distal portion
This transporter usually reabsorb 5% only (low efficacy)
Ions with increased excretion and the other with decreased under the effect of thiazide
Na+ and K+ increased excretion and cl-
Decreased excretion : Ca2+
Uses of thiazide diuretics
1-
2-
3-
Hypertension
Edema associated eith heart failure
Nephrolithiasis (kidney stones) with hypercalciuria (because thiazides decrease Ca in urine)
Thiazide like analogs like—– at low levels show—–
Others included in this class like—
Indapamine(fludex LP)
Low hypertensive action
Hydrochlorothiazide (Esidrex)
Carbonic anhydrase inhibitors:
Mode of action
Location
Effect
Name of drugs included
Ofher usage of the drug
Efficacy
Inhibit carbonic anhydrase which lead to less sodium bicarbonate absorption at the proximal tubule
Decrease sodium potass and bicarbonates reab
Acetazolamide(Diamox) ; used in ophtalmo for tx of glaucoma
Much less efficacious than loop and thiazide
Ions increased in urine
Ions decreased
Na+
K+
HCO3-
No ions decreased in urine
Mechanism of action of CAI on slide
Potassium sparing diuretics include —– and ——
Aldosterone antagonist (spironolactone aka aldactone) and sodium channels blockers
ENaC inhibitors include—- and —–
Mode of action:
Location of action:
Benefits:
Adverse effects:
Amiloride
Triamterene
Late Distal and collecting tubule
Prevent hypokalemia caused by thiazide and loop diuretics
Hyperkalmeia is the main adverse effect
Ions incr and decreased after usage of k sparing diuretics
Decreased K+
Na+ increased
Osmotic diuretics:
Mode of action:
Examples:
Inhibit reabsorption of water and Na+
Increasing the osmolarity of blood and renal filtrate
Glycerol and mannitol
Usages of osmotic diuretics
Tx for IC pressure
List the adverse effects of :
Thiazide
Loop
K+ sparing
Thiazide: hyperglycemia,hypokalemia,hyponatremia,hyperuricemia
Loop: hypokalemia hyponatrmia, metabolic alkalosis, hypomagnesemia,hyperuricemia and dehydration
K+sparing; peptic ulcer, metabolic acidosis hyperkalemia,gynecomastia and menstrual irregularities
List the drug interactions of:
Thiazide:
Loop:
K+ sparing
All with NSAIDs have lower drug efficacy
Thiazide: beta blockers potentiate hyperglycemia
Corticosteroids enhance hypokalemia
Loop: Corticosteroids enhance hypokalemia, aminoglycosides cause nephrotoxicity
