Proximal tubule diuretics

This group of diuretics includes carbonic anhydrase inhibitors, which inhibit bicarbonate reabsorption in the proximal tubule with subsequent bicarbonate diuresis. Significant bicarbonate losses can lead to metabolic acidosis. However, the effect gradually decreases over several days. The cause is increased NaCl reabsorption, which leads to acidosis.

Representatives
Acetazolamide Dorzolamide

The two main representatives are:


 * acetazolamide ,
 * dorzolamide.

Indication
The main indication is glaucoma therapy. The ciliary body secretes bicarbonate into the intraocular fluid by a mechanism similar to tubular reabsorption, but in the opposite direction. It can also be blocked by carbonic anhydrase inhibitors, leading to a decrease in the amount of intraocular fluid. Dorzolamide is given as eye drops. Another indication is the correction of metabolic alkalosis and prophylaxis and treatment of altitude sickness.

Side effects and toxicity

 * Metabolic acidosis.
 * Kidney stones - Phosphaturia and hypercalciuria develop during bicarbonate diuresis. Under these conditions, calcium salts become potentially insoluble at alkaline pH, thus meeting the conditions for stone formation.
 * Hypokalaemia.
 * CNS disorders - confusion, drowsiness.

related articles

 * Diuretics
 * Renin-angiotensin-aldosterone system
 * Hypertension
 * Hypertensive crisis

Source

 * MARTÍNKOVÁ, Jiřina, Stanislav MIČUDA and Jolana CERMANOVÁ. Selected chapters from clinical pharmacology for bachelor study: Cardiovascular system  [online]. © 2000. [feeling. 2010-07-02]. < https://www.lfhk.cuni.cz/farmakol/predn/bak/kapitoly/prednasky/kardio-bak.ppt/ >.