18. Cardiology - Diuretics INCOMPLETE Flashcards
Give an example of a thiazide diuretic.
Bendroflumethiazide.
What is the naming rule of loop diuretics? Give an example.
-ide. Furosemide, bumetanide.
What is the naming rule of potassium-sparing diuretics? Give an example.
-one. Spironolactone (also amiloride).
Give an example of a carbonic anhydrase inhibitor.
Acetazolamide.
Give an example of an osmotic diuretic.
Mannitol.
What are the five functional zones of the nephron?
Proximal convoluted tubule, descending loop of Henle, ascending loop of Henle, distal convoluted tubule, collecting tubule and duct.
What is reabsorbed in the PCT?
Glucose, amino acids, Na+, K+, H2O.
What is reabsorbed in the ascending loop of Henle?
Na+, K+, Cl-.
What is reabsorbed in the distal convoluted tubule?
Cl-, Na+.
What is secreted in the collecting tubule and duct?
H+ and K+.
What is reabsorbed in the collecting tubule and duct?
H2O.
Where do thiazide diuretics act?
In the distal convoluted tubule.
Why are thiazide diuretics sometimes called “low ceiling diuretics”?
Because increasing the dose above normal therapeutic doses doesn’t promote further diuretic response.
What is the mechanism of action of thiazides?
Act in cortical region of ascending loop of Henle and distal convoluted tubule to inhibit Na+/Cl- cotransporter on luminal membrane of tubule and reduce Na+ reabsorption. So increased Na+ and Cl- in tubular fluid.
What can reduce the efficacy of thiazides?
Decreased renal function, e.g. from concomitant use of NSAIDs.
What is the impact of urinary excretion of Ca2+, K+, Na+ and volume of urine due to thiazide use?
Decreased Ca2+ excretion, increased excretion of Na+, K+, and volume of urine.
What are the therapeutic uses of thiazide diuretics?
Hypertension, heart failure, hypercalcuria, diabetes insipidus.
What are the five main ADRs of thiazide diuretics?
Hypokalaemia, hypuricaemia, hypotension, hyponatraemia, hypercalcaemia.
How can hypokalaemia be avoided in thiazide diuretic use?
Supplemented by dietary measures or supplements. If RAAS –> aldosterone release –> worsened hypokalaemia, then spironolactone or other K+ sparing diuretics should be used too.
How do thiazide diuretics cause hyponatraemia?
Elevated ADH from hypovolaemia.
How do thiazide diuretics cause hyperuricaemia?
Increased uric acid by decreasing amount of acid excreted by organic acid secretory system.
In what scenario is metolazone (thiazide-like diuretic) considered over thiazide diuretics?
Advanced renal failure, it can still cause Na+ excretion.
GOT TO IV. LOOP OR HIGH-CEILING DIURETICS
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