3.1.4 Thiazides Flashcards
How do thiazide and thiazide-like diuretics work?
Inhibit the NCL transporter in the DCT
Less Na+ and H2O reabsorption (long term RAAS compensates)
Long-term effects mediated by sensitivity of vascular smooth muscle to vasoconstrictors Ca2+ and NorAd
e.g Indapamide
When are diuretics more useful than CCBs?
In oedema
What adverse effects can happen with diuretics?
Hypokalaemia
Hyponatraemia
Hyperuricemia (gout)
Arrhythmias
Increased glucose (especially with Beta blockers)
Slight increase in cholesterol and trigylcerides
When can thiazides not be given?
Hypokalaemia
Hyponatraemia
Gout
What are some important drug reactions with thiazides?
NSAIDs
Drugs that decrease K+, e.g. loop diuretics
Why do you get hyperuricaemia/ gout with thiazides?
Thiazides also inhibit the uric acid transporter, this leads to an accumulation of uric acid in the blood that would normally be cleared
Uric acid then forms crystals in joints leading to gout
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PAIN
Why are ACEi/ARB used in hypertension in those with T2DM?
ACEi/ARB decreases diabetic nephropathy and CKD with proteinuria by dilation of EA
Dilation of EA reduces pressure
Two pronged approach, reducing peripheral resistance and BP + dilating EA
What is spironolactone?
Aldosterone (mineralocorticoid) receptor antagonist
What are the adverse effects of spironolactone?
Hyperkalaemia
Gynaecomastia
When can spironolactone not be given?
Hyperkalaemia
Addison’s
Pregnancy
Anuria
Important drug interactions for spironolactone
Drugs increase K+
Alcohol
Amiloride
ACEi
ARBs
When are alpha/beta blockers considered over spironolactone?
If [K+] range is > 4.5mmol
What beta blocker is used during pregnancy?
Labetalol
Why does spironolactone cause gynaecomastia?
Also acts on androgen receptors, therefore more circulating androgens, androgens are aromatised to oestrogen, therefore you start to develop breast tissue
Oestradiol is also displaced from sex hormone binding globulin
