PPT 2 Flashcards
What is mannitol?
Osmotic diuretic
What is acetazolemide?
Carbonic anhydrase inhibutor - diuretic
Reduces Na/H+ exchange so more Na in filtrate and more water loss
What is furosemide?
Loop diuretic
NKCC2 inhibitor
How do thiazide diuretics work?
Blocks Na/Cl transporter in the DCT and causes more potassium excretion because more Na reaches the collecting duct
In the collecting duct, Na is absorbed in exchange for the secretion of K+
*amiloride blocks this exchanger
Discuss K+ sparing diuretics
Amiloride: blocks Na+/ K+ exchanger in collecting duct - means less Na+ is absorbed and therefore less K+ is excreted
Spirololactone: blocks the aldosterone receptor, the activation of the aldosterone receptor normally causes more Na/K channels to be placed in the membrane
How does anti diuretic hormone work?
AKA vasopressin, secreted by posterior pituitary
- Causes more AQP2 to be place in collecting duct membrane and promotes water uptake
Discuss the role of urine pH in drug excretion
Acidic urine: alklaine drug more readily ionised and therefore more easily excreted
Alkaline urine: acidic drug more easily excreted
What would be given in the case of an aspirin overdose?
Sodium bicarbonate - makes urine more alkaline and promotes loss of salicylic acid (aspirin metabolite)
What is tamulosin?
Alpha 1a blocker, relaxes muscle fibres in prostate and bladder neck and allows for easier micturition
Which drugs increase GFR?
Afferent dilators: Atrial natriuretic peptide, prostaglandins
Efferent constrictors: angiotensin II and ANP (by blocking affect of noradrenaline)
How do NSAIDs affect the kidney?
Contrict the afferent arteriole and therefore reduce GFR
Why are ACEi and ARB contraindicated in renal artery stenosis?
Renal artery stenosis = GFR low
ACEi and ARB = dilate efferent arteriole and decrease GFR even further
