Diuretics

Question 1

Carbonic Anhydrase Inhibitors

Answer 1

👾👾act mainly at the PCT to prevent action of carbonic anhydrase in the tubule, which in turn affects the reabsorption rate of Na + ions. 🤮🤮🤮🤮🤮It is rarely used as a diuretic due to risk of metabolic acidosis and hypokalaemia, yet is given as a topic treatment for 👁glaucoma.

👉🏿👉🏿👉🏿 loss of Na K, Po3 HCO3

Question 2

Carbonic anhydrase inhibitors

Answer 2

Ex. Aceta-zolamide,

dor-zolamide

Question 3

Osmotic Diuretics

Answer 3

such as 👉🏿Mannitol, act to 👾👾increase the osmotic gradient systemically (including in the renal tubules). Like the carbonic anhydrase inhibitors,
🤮🤮they are rarely used as diuretics now due to excessive water loss and causing hypernatraemia. They are 🧠🧠currently used in severe cerebral or pulmonary oedema.

Question 4

ADH Antagonists

Answer 4

reduce the concentrating ability of urine in the collecting ducts and include both lithium and demeclocycline.

Question 5

Thiazides

Answer 5

whilst also promoting Ca 2+ reabsorption (so can be helpful in limiting calcium loss and preventing kidney stone formation). They have the risk of causing hypokalaemia, hypercalcaemia, and hyperuricaemia (to predispose to causing gout), as well as risk of erectile dysfunction.

Question 6

Potassium-Sparing Diuretics

Answer 6

They should not be used alongside ACE inhibitors due to the risk of hyperkalaemia.

Question 7

Aldosterone Antagonists

Answer 7

Aldosterone antagonists, such as Spironolactone or Eplerenone, 👾👾👾act to inhibit the action of aldosterone on the mineralocorticoid receptors, thus affecting Na + -K + -ATPase and ENaC protein synthesis. Spironolactone’s active metabolite is canrenone, which has a t 1/2 of 18-24 hours thus allowing longer term use. Its main 🤮🤮ADRs are causing hyperkalaemia and also some androgenic cross-reactivity, thus may cause gynaecomastia.

Its👉🏿👉🏿👉🏿 main indications for use are in heart failure, hypertension, liver failure, or hyperaldosteronism (such as Conn’s syndrome). There are no real DDIs concerned with aldosterone antagonists.