Diuretics Flashcards
Name 2 thiazide diuretics
Bendroflumethiazide
Indapamide
What is the mechanism of action of the thiazide diuretics?
Inhibit the Na+/Cl- co-transporter in the DCT, hence reducing Na+ retention
What are the indications for thiazides?
Hypertension
Heart failure
List 4 ADRs of thiazides
- Hypokalaemia
- Hyponatraemia
- Hyperglycaemia
- Dyslipidaemia
Are there any drugs which interact with thiazides?
Yes -
- NSAIDs
- Digoxin
- B-blockers
- Carbemazepine (and more)
What sort of diuretics are furosemide and bumetanide?
Loop diuretics
What is the mechanism of action of the loop diuretics?
- Blocks the NKCC2 channels in the thick ascending limb of the loop of Henle, hence reducing sodium retention
How potent are the loop diuretics?
Hence what are they used for?
Highly potent
Used in fluid overload, such as:
- Heart failure - pulmonary and peripheral oedema
- Ascites due to liver failure
List 4 ADRs of the loop diuretics
- Hypokalaemia
- Hyponatraemia
- Hypovolaemia
- Ototoxicity
List 2 DDIs with loop diuretics
Aminoglycosides - increase nephrotoxicity/Ototoxicity
NSAIDs
Name 2 drugs which are potassium-sparing diuretics.
What are their mechanisms of action?
- Spironolactone - aldosterone antagonist - inhibit action of aldosterone, therefore reduces expression of ENaC and Na+/K+-ATPase in principal cells of CD.
- Amiloride - inhibits ENaC in the late DCT/CD
What are the indications for Spironolactone?
- Ascites
- Hypertension caused by hyperaldosteronism, e.g. Conn’s
List some important ADRs of Spironolactone
- Can have steroid-hormone type effects - gynaecomastia/irregular periods
- Liver impairment
- Hyperkalaemia
What drug interaction must be considered with Spironolactone?
- Anything K+ sparing - will cause hyperkalaemia
- Important example = ACEi
What is the indication for use of Amiloride?
List a couple of ADRs and DDIs
- Weak - used alongside loop/thiazides
- ADRs: GI upset, hypotension
- DDIs: anything K+-sparing - ACEi
