Diuretics

Question 1

name 3 loop diuretics
what is the most potent one?

Answer 1

bumetanide (most potent)
furosemide
torasemide

Question 2

what loop diuretic can aggravate gout?

Answer 2

furosemide

Question 3

name 4 thiazide diuretics

Answer 3

bendroflumethiazide
indapamide
chlortalidone
metolazone

Question 4

what thiazide diuretic works in severe renal failure?

Answer 4

metolazone

Question 5

what thiazide diuretic is least likely to aggravate diabetes?

Answer 5

indapamide

Question 6

name 2 aldersterone antagonists
what one is used for ascites in liver failure?

Answer 6

spironolactone - used for ascities
eplerenone

Question 7

name 2 potassium sparing diuretics
what one can cause blue urine in some lights?

Answer 7

amiloride
triamterene (blue urine)

Question 8

name an osmotic diuretic and what its indications?

Answer 8

mannitol - used in cerebral oedema and high intracrainal pressure

Question 9

name a carbonic anhydrase inhibitor and its indication

Answer 9

acetozolamide - used in glaucoma

Question 10

what is the principle behind how diuretics work?

Answer 10

• they increase urine output by the kidneys
• promote diuresis by inhibiting sodium reabsorption at different parts of the nephron

Question 11

how do loop diuretics work?

Answer 11

inhibits Na+/K+/Cl- in ascending loop of henle

Question 12

whats the onset and duration of action for loop diuretics?

Answer 12

onset = 1 hr
duration of action = 6hrs

Question 13

what condition are loop diuretics cautioned in?

Answer 13

benign prostatic hyperplasia

Question 14

what are some symptoms you need to look out for in patients on loop diuretics (reasons to use with caution) - 3 points

Answer 14

1. diabetes mellitus - latent diabetes may become overt, and insulin requirements in people with established diabetes may increase (reduce dose)
2. hearing impairment (ototoxicity) - as a result of hypoproteinaemia from furosemide which increases risk of ototoxicity (reduce dose)
3. Gout - furosemide raises uric acid levels

Question 15

what electroytes are raised/decrease with loop diuretics?

Answer 15

hypO K+, Na+, Cl-, Mg2+, Ca2+

Question 16

why are loop diuretics contraindicated/cautioned in alcoholic/liver cirrhosis?

Answer 16

due to already low levels of K+, Na+, Cl-, Mg2+

Question 17

whats the usual dose of furosemide in HF?
How many times are diuretics given a day?

Answer 17

20 - 40mg OM
usually diuretics given BD in HF (last dose at lunch/early afternoon)

Question 18

how do thiazide diuretics work?

Answer 18

inhibits Na+/Cl- transporter in distal convoluted tubule

Question 19

whats the onset and duration of thiazide diuretics?

Answer 19

1 - 2 hour onset
12 - 24 hrs duration of action

Question 20

name 3 common SE to monitor in thaizides?

Answer 20

1. GI disturbances
2. Impotence (erectile dysfunction)
3. high LDL/triglycerides

Question 21

in what conditions should thiazide-like diuretics be prescribed with cautions?

Answer 21

1. diabetes - can cause hyperglycaemia
2. gout - hyperuricaemia
3. systemic lupus erythematosus
4. severe CV disease or those treated with cardiac glycoside due to danger of hypokalaemia in these patients

Question 22

whats the difference in electrolyte disturbances between loop and thiazide diuretics?

Answer 22

loop diuretics cause low everything where as thiazide cause low K+, Na+, Mg2+, Cl- but HIGH Ca2+

Question 23

both loop and thiazide diuretics are indicated for heart failure, but what additional indication do thiazide diuretics have?
What are the differnet starting doses for each indication?

Answer 23

hypertension
HF = 5mg OM
HTN = 2.5mg OM

Question 24

what thiazide has the longest t1/2?
what can you do if the patient dislikes frequent urination?

Answer 24

chlortalidone
give on alternate days

Question 25

how do K+ sparing diuretics work?

Answer 25

promotes urination without the loss of K+ by inhibitng Na+ in the distal convoluted tubule

Question 26

what class of diuretic is classed as a weaker diuretic?

Answer 26

potassium-sparing (often used as an adjunct to loop and thiazide)

Question 27

when may potassium sparing diuretics be used?
what’s there main SE?
what interactions should you look out for?

Answer 27

to counteract hypokalemia
SE = hyperkalaemia
Interactions = avoid drugs causing high K+ (supplements, ACEi/ARB, aldersterone antagonist)

Question 28

how do aldersterone antagonists work?

Answer 28

inhibits aldersterone which causes sodium reabsorption via the K+/Na+/H+ co-transporter. Less potassium and hydrogen ions are exchanged for sodium therefore less lost to the urine

Question 29

what are 4 key SE of spironolactone? (inc electrolyte disturbances)

Answer 29

1. gynaecomastia - benign breast tumours, menstural distubacnes
2. hypertrichosis
3. change in libido
4. hypERkalaemia, hypERuraemia, hypOnatraemia

Question 30

what interactions should you look out for with aldersterone antagonists?

Answer 30

any drugs also causing high potassium

Question 31

what was the MHRA warning for aldersterone antagonists?

Answer 31

potentially fatal/severe hyperkalaemia. Monitorng blood electrolytes essential

Question 32

how do osmotic diuretics work?

Answer 32

inhibis sodium and water reabsorption by increasing the osmolarity (solute conc) of blood and renal filtrate. Osmotic diuretics act on the parts of nephron that are water permeale; proximal convoluted tubule and descending loop of henle

Question 33

what should you avoid thiazide diuretics in patients with renal impairment?

Answer 33

CrCl <30ml/min

Question 34

what class of diuretic may you need to increase dose of in renal impairment?

Answer 34

loop