my q's: renal diuretics

Question 1

the types of renal medications used in practice

Answer 1

1. Frusemide
2. Spironlactone
3. Thiazide medicines
   - these 3 all act directly on the kidney and are first line meds (most used/common)
4. mannitol
   - doesnt act directly on the kidney, but has osmotic effect
5. acetazolamide
   - reduces intra-ocular pressure (again doesn’t act directly on kidney)

Question 2

association with cardiovascular disease & renal problems

Answer 2

• water retention/oedema is associated with CV disease
• if there’s an accumulation of fluid (pulmonary oedema) due to incoordination of venous return and cardiac output
• this can lead to a blockage and reduce the amount of blood pumping throughout the body, which can cause kidney disease
• therefore, the use of diuretics will reduce salt & water retention by increasing urination
• this releases the fluid accumulation and oedema

Question 3

how Frusemide works:

Answer 3

• the loop of Henle’s function is to reabsorb Na+, K+ and Cl using the Na+K+ATPase pump
• Na+ is pumped into the interstitium (tissues) creating a gradient that draws Na+ into the loop of Henle

so, Frusemide blocks the Na+K+ATPase pump, and instead of all the Na+ being reabsorbed, so K+ is lost instead

Question 4

how Spironolactone works:

Answer 4

• The collecting duct will reabsorb Na+ and H2O using the Na+K+ATPase pump, which is under the control of aldosterone, eventually leading to increased fluid retention

so, Spironolactone stops aldosterone therefore Na+ isn’t reabsorbed & the loss of K+ is reduced too

Question 5

how do Thiazide diuretics work:

Answer 5

• Thiazide diuretics inhibit reabsorption of Na+ and Cl from the distal tubules and block the Na+ cl co-transporter

Question 6

Mannitol MOA

Answer 6

• has an osmotic effect by extracting water from extravascular fluid

Question 7

more on Frusemide

Answer 7

• most commonly used
• given to small animals & horses
• IV or IM twice daily
• most potent
• also given for congestive heart failure

Question 8

side effects of diuretic medicines

Answer 8

• dehydration due to increased urination

- if extreme can result in hypovolemia

Question 9

more on Spironolactone

Answer 9

• if there’s a concern about the loss of K+, it will be used over frusemide

Question 10

more on Mannitol

Answer 10

• given as slow IV infusion over 15-30 mins
• gives relief within 15 mins - fast acting
• hyperosmotic solution (when cooled down, can crystalize) therefore need to reheat in microwave/water bath at 70 degrees and then cool to room temp, ensure there’s no crystals
• used for cerebral oedema