Diuetics Flashcards
What are they
Help reduce fluid buildup in the body and any substance that promotes the increased production of urine
What are they used for
Treatment of hypertension but also oedema
oedema/
Excessive water in the body
How do thy work
Inhibiting the reabsorbtion of ions - Na+ - which gives a higher osmolarty in the kidney tubule and hence more excretion of wtater
Classes
Thiazides - bendroflumethozide
Loop - furosemide
K sparing - spironolactone
Carbonic anhydrase - acetazolomide - no longer used
Osmotic - mannitol - not used
Proximal tubule
Reabsorbtion of most solutes and water occur here
60-70% of Na and water and 98% glucose reabsorbtion happen in proximal
Most Na is rebsorbed via Na+-H+ exchanger
pH regulation
H ions exerted and bicarbonate ions absorbed
What acts in the proximal tubule
Carbonic anhydrase inhibitors to have ther diuretic effect
Carbonic cnhydrase in proximal
Na move in down its gradient and allows H ions to move up gradient into tubule. Carbonic anhydrase takes water and makes carbonic acid which separates into protons and a bicarbonate which can be transported into blood. These are the H that move out as the Na move in. Na can be pumped out into blood.
If no H ions - proximal
Carbonic anhydrase inhibitor will block the carbonic anhydrase so less carbonic acid and less H ions so less Na being reabsorbed. Na remain in tubule and have diuretic effect.
Loop of Henle
Water is reabsorbed in descending loop. Na an Cl is reasoned in the ascending loop without water
Loop diuretics act at the ascending loop - inhibit the Na, K, Cl co-transporter
Loop diuretics
Low Na in cell.
C1 is a cotransprter taking ions in , from inside the kidney tubule to inside the cell.
Na goes down its gradient and allows other ions to move up their gradients and into cell.
Now Na can now be pumped out again with NaK ATPase.
K can also move out by KCl exchanger with Cl moving into blood.
Diuretic effect = block transporter C1means more Na, more K in the loop tubule, more ion and more water so more urine
Lop diuretics and hypokalaemia
They lower blood pressure by helping the body pass sodium and water through the urine. Some diuretics also cause the body to pass more potassium in the urine. This can lead to low potassium levels in the bloodstream, also called hypokalemia.
Distal tubule
Na and Cl are reabsorbed here without water
Thiazides diuretics work here inhibiting Na, Cl, cotranspoerter/symporter
Thiazides diuretics