Diuretics Flashcards
Thiazide diuretics MOA
Inhibits sodium re absorption and so water, at the beginning of the distal convoluted tube
How do diuretics affect urine output
Increases urine output
What are examples of thiazides
Thiazide like
Bendroflumethiazide
Chlortalidone
Indapamide
Whats the onset and duration of action of thiazides of oral administration
Onset is 1-2 hours
Duration is 12-24hrs
What time of day do you give diuretics and why
Morning, to avoid diuresis at night interfering with sleep
Whats the potency of bendroflumethiazide, indapamide and chlortalidone
Moderate potency
When are lower doses of thiazides used and when are higher doses used
Lower doses are used in hypertension and higher doses are used in oedema due to congestive HF
Do higher or lower doses of thiazides have more affect on biochemical balance (electrolytes)
Higher doses
When is bendroflumethiazide used? Conditions
Mild or moderate HF or hypertension , oedema
Which thiazide can be given on alternate days and why?
Whats it’s indication?
Oedema and hypertension and HF
Chlortiladone
Because its long acting
Indication for indapamide
Hypertension
It is now first line
Bendroflumethiazide can be used first line if already stable on it
Why is indapamide preferred in comparison to bendro in hypertension
Less aggravation of diabetes and lowers BP without having a great affect on electrolytes
What are thiazides contraindicated in.
Hint: electrolytes
Hypokalaemia, addisons disease,
Hyponatraemia, hypercalcaemia, hyperuricaemia
Which diuretic has greater risk of hypokalaemia?
Thiazides
Which drug interacts with thiazides and what can you give instead?
Thiazides interact with cardiac glycosides such as digoxin due to hypokalaemia risk
Give potassium sparing diuretic or potassium supplements
Hypokalaemia is dangerous in ….
Severe cardiovascular disease
In liver disease hypokalaemia can lead to ….. especially in ……. Hence avoid using …… in liver disease
Encephalopathy
Alcoholic cirrhosis
Thiazides
What thiazide doses would you initially give to elderly and why
Low doses
More prone to SE
What are the SE of thiazides
Skin reactions, constipation, electrolyte imbalance, PH
Dont use thiazides in long term treatment of ….. instead recommend …..
Gravitational oedema
Raise legs, increased movement, stockings
What do thiazides exacerbate. Why?
Diabetes
Gout
Due to hyperuricaemia and hyperglycaemia
In gestational hypertension can we give thiazides? Why?
No
Can cause malformations, neonatal thrombocytopenia, electrolyte imbalance, bone marrow suppression and jaundice
Can we use thiazide diuretics in severe liver disease? Why?
No
Causes hypokalaemia which in liver disease causes encephalopathy
Dont use thiazides if eGFR ….. because…..
<30ml/min/1.73
Ineffective
What are examples of loop diuretics?
Furosemide
Bumetanide
Loops MOA
Inhibits reabsorption of Na and water from the ascending loop of henle
Indications of loops (furosemide, bumetanide)
Pulmonary Oedema in HF, and in Resistant hypertension
Which diuretics are stronger and which can be used for resistant oedema?
Loop diuretics are stronger and can be used for resistant oedema
Hyperglycaemia is more likely in loops or thiazide diuretics?
Thiazides
Which diuretic is more powerful? Loop or thiazide
Loop
Loop diuretics can exacerbate…..
Diabetes and gout
Diabetes more exacerbated in thiazide use
Onset of furosemide and bumetanide and duration
1 hour
Diuresis is complete within 6 hours hence can be given BD without interfering with sleep
CI of loop (furosemide and bumetanide)
Renal failure (eGFR <30), severe hypokalaemia, hyponatraemia, liver cirrhosis
In ….. impairment, loops can cause ……. At higher doses or IV administration
Renal impairment
Ototoxic - deafness and tinnitus
Why are loops CI in renal impairment
Higher doses cause deafness/ ototoxic
What colours the urine blue
Triamterene and furosemide
Which diuretics are classed as ‘weak’ and which are classed as powerful
Amiloride and triamterene - weak
Bumetanide, furosemide are powerful
Can you give spironolactone and potassium supplements
No because of hyperkalaemia risk
Which drug is CI with potassium sparing diuretics
ACEi/ARBs
Which potassium sparing diuretics are strong
Spironolactone and epleronone
What is a SE of spironolactone
Gynaecomastasia (breast tenderness)
When is combination diuretic therapy used?
When oedema is resistant to one diuretic
Whats an example of an osmotic diuretic and whats its indications?
Mannitol
Cerebral oedema and raised ocular pressure
Give an example of a carbonic anhydrase inhibitor
Whats its indication
Acetazolamide - weak diuretic
Glaucoma, epilepsy
Dont give acetazolamide if pt is allergic to….
Sulfonamide
Can you give acetazolamide in renal and hepatic impairment?
Explain
No
Hepatic - hypokalaemia causes encephalopathy
Renal- risk of metabolic acidosis
Whats the drug class of brinzolamide and dorzolamide? Indications?
Used in open angle glaucoma and raised intraocular pressure when BB ineffective or CI
and inhibits formation of aq humour
Can you give NSAIDS with diuretics
No
Increased Risk of acute renal failure
Which is more potent furosemide ir bumetanide
Bumetanide
