Diuretics

Question 1

In what 2 general ways do osmotic diuretics work?

Answer 1

Increase filtrate osmolarity - washing out and depleting the corticomedullary gradient for reabsoprtion in PCT and descending tubule

Less reabsorption -> less filtrate -> reduced flow rate of urine -> reduced contact time with epithelium -> reduced Na reabsorption

Question 2

Name a carbonic anhydrase inhibitor.

Answer 2

Acetazolamide

Question 3

Give 4 clinical uses of loop diuretics.

Answer 3

Heart failure symptoms
Acute pulmonary Edema
Fluid retention (nephrotic syndrome, cirrhosis and renal failure)
Hypercalcemia

Question 4

Why can thiazides lead to increased Ca2+ reabsorption?

What is another adverse effect of thiazides?

What is a clinical use of thiazide diuretics?

Answer 4

Diminish Na concentration in the cell

Increased activity of NaCa antiporter on basolateral membrane.

Hypokalemia

Hypertension

Question 5

Give 4 clinical uses of aldosterone antagonists.

Answer 5

Long term heart failure treatment
Ascites and oedema in cirrhosis
Hypertension (not control by ACEI + CCB + Thiazide)
Cons syndrome related hypertension

Question 6

When are K+ sparing diuretics contraindicated?

Answer 6

K+ supplement use and if renal function is impaired.

Question 7

Give some adverse effects of diuretics.

Answer 7

Hypovolemia 
Hyponatremia 
Hyperuricaemia (gout) 
Metabolic effects (thiazides and loops) 
- glucose intolerance and increased LDL 
Erectile dysfunction (thiazides) 
Spironolactone (gynaecomastia)

Question 8

What is a adverse effect of carbonic anhydrase inhibitors?

What are they used to treat?

Answer 8

Metabolic acidosis

Glaucoma