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CVPR - CV Unit 1 > Diuretics > Flashcards

Flashcards in Diuretics Deck (15):
1

Loop Diuretics - Mechanism

Acting on the ascending limb of the Loop of Henle to inhibit NaCl transport; more Na+, K+, and Cl- is retained in the urine

2

Loop Diuretics - Pharmacokinetics

Rapid oral absorption, excreted by renal filtration; duration of effect is 2-3 hours (Furosemide)

3

Loop Diuretics - Prototypical

Furosemide

4

Clinical usages of diuretics

Heart failure patients with volume overload; Furosemide is first line; bumetanide and tosemide for refractory congestion

5

Loop Diuretics - Adverse Effects

Hypokalemic metabolic alkalosis due to enhanced secretion of K+ and H+
Ototoxicity
Hyperuricemia
Hypomagnesemia

6

Thiazides - Mechanism

Act on the convoluted tubule to inhibit the NaCl transporter; increases urinary excretion of NaCl with modest diuretic effect

7

Hydrochlorothiazide - Pharmacokinetics

Oral absorption, secreted by organic acid secretory system

8

Hydrochlorothiazide - Adverse Reactions

Hypokalemia
Hyperuricemia
Impaired carbohydrate tolerance (hyperglycemia, glucosuria) and hyperlipidemia

9

Mechanism of coupling Na+ reabsorption with K+ excretion

In the collecting tubule the driving force for Na+ into the cell exceeds that for K+ exit; Na+ enters the cell and the lumen becomes electronegative, driving Cl- into cells and K+ into the urine

10

Aldosterone Antagonists - Example

Spironolactone

11

Spironolactone - Mechanism

Competitively inhibits the aldosterone receptor, preventing the effect of the aldosterone TF to increase the number and activity of Na+ and K+ membrane channels; blockade of the aldosterone effect means that less Na+ is reabsorbed from the collecting duct, the lumen potential becomes positive, and less K+ moves into the urine

12

Uses of Spironolactone

Added to therapy for LVEF < 30% on ACEI/ARB and B-blocker therapy

Adds additional diuresis plus antiremodeling effect

Monitor serum K+ and GFR

13

Spironolactone - Adverse Effects

Hyperkalemia, arrhythmias
Endocrine abnormalities (gynecomastia via secondary blockage of androgen receptor)

14

K+ sparing diuretics - 3 examples

Spironolactone
Amiloride
Triamterene

15

Amiloride & Triamterene

Class of K+ sparing diuretics that work by blocking Na+ channels on collecting duct lumen to decrease Na+ reabsorption and thus decrease coupled K+ secretion