Carbonic anhydrase inhibitors

Question 1

example

Answer 1

acetazolamide

Question 2

carbonic anhydrase inhibitors are no longer used for what

Answer 2

as a diuretic

Question 3

what are carbonic anhydrase inhibitors used in

Answer 3

• glaucoma (reduce intra-occualr pressure by reducing the production of aqueous humour)
• prophylaxis of acute mountain sickness
• some forms of infantile epilepsy
• alkalinising the urine along with other agents (citrate slats which are given orally which generated bicarbonate) used in dysuria, preventing formation of uric acid stones

Question 4

general mechanism of action

Answer 4

reduces re-absorption of bicarbonate in the proximal convoluted tubule which reduces sodium re-absorption

Question 5

in the proemial convoluted tubule

Answer 5

bicarbonate re-absorption is initiated by the Na/H+ exchange on the apical membrane, CO2 enters the tubule from the blood and combines with water to form carbonic acid which then dissociates via carbonic anhydrase to form H and HCO3-, the H+ ion is then moved into the blood via the Na/H+ ANTE-PORTER ON THE APICAL MEMBRANE, the H+ moved into the tubule then combines with HCO3- to form carbonic acid which then dissociates to form H+ and HCO3- via carbonic anhydrase and the bicarbonate then re-enters the cell via diffusion

Question 6

carbonic anhydrase inhibitors inhibit

Answer 6

the affect of carbonic anhydrase therefore, bicarbonate remains in the lumen, since bicarbonate re-absorption utilises the sodium/H+ PUMP less sodium is re-absobred causing a diuresis

Question 7

however, the diuresis caused by carbonic anhydrase inhibitors

Answer 7

is mild as most of the sodium not re-absorbed just gets re-absorbed further on in the tubule

Question 8

side affects

Answer 8

hypokalaemia and metabolic acidosis