diuretics

Question 1

where in the nephron are sodium and chloride (and therefore water) mostly reabsorbed?

Answer 1

15-25% in the loop of henle

10% in the DCT

Question 2

what diseases are diuretics often needed for and why?

Answer 2

CHF
HT
pulmonary oedema
liver cirrhosis/disease
renal impairment 

because excess blood volume increases cardiac workload

Question 3

what are the most common types of diuretics and what sites do they target?

Answer 3

loop - nephron loop

thiazide - early DCT

potassium-sparing diuretics - late DCT

Question 4

compare and contrast the efficacy of various diuretics

Answer 4

loop diuretics - powerful

thiazides - moderately potent

K+ sparing - weak

Question 5

adverse effects of both loop and thiazide diuretics?

Answer 5

hypokalaemia 
hyponatraemia
hypotension
increased uric acid (gout)
ototoxicity
GI upset

Question 6

adverse effects of both K+ sparing diuretics?

Answer 6

hyperkalaemia

hyponatraemia
hypotension

Question 7

mechanism of action of K+ sparing diuretics, including spironolactone?

Answer 7

blocks action of aldosterone, preventing sodium reabsorption (ergo water) and retaining potassium

Question 8

MOA of thiazide diuretics?

Answer 8

inhibits sodium and chloride reabsorption by binding to Na+/Cl- transporter in early DCT

also increases K+ secretion

Question 9

MOA of loop diuretics?

Answer 9

inhibits Na+, Cl- and K+ transporters in ascending limb of nephron loop, causing reduced reabsorption of this electrolytes, concurrent water loss in urine, decreased blood volume

Question 10

important considerations for hypertensive pts on diuretics

Answer 10

diuretics alone are not sufficient to manage HTN, as decreased blood volume = decreased GFR = increased renin = HTN

need to be used in conjunction with a hypertensive med