Question

Diuretics can be prescribed to combat edema and high blood pressure. Thiazide is one of the most common. Describe its mechanism of action and how it combats the two issues listed.

Answer 1

Thiazides are a class of diuretics(Drugs that increases Urine Output).They can be used to treat conditions like Edema and High blood pressure.

Examples of thiazides-

1.Chlorothiazide

2.HydroChlorothiazide

3.Chlorthalidone.

Mechanism of Action of thiazides-

*They inhibit Na+-Cl- cotransporter,which is present in the DCT( distal convoluted tubule of a nephron).

This Na+Cl- cotransporter is responsible for the reabsorption of Na+ in the DCT.

(It reabsorbs sodium and chloride ions from the tubular fluid to the cells of DCT)

When Na+ is Reabsorbed ----------There will be Reabsoption of H2O.(Fluid inside cells of DCT become Hyper tonic than Tubular fluid,so there is absorbtion of H2O)-----So Urine Volume Reduces.

So if this cotransporter is Inhibited there is reduced Reabsorption of Na+----Reduced reabsorption of H2O-----More Urine Output.

So when the Urine Output is Increased so Edema will be Relieved.(Edema is caused due to extra fluid and sodium in the circulation.).

Also Blood pressure is reduced.

(Blood pressure is the lateral pressure Exerted by Cloumn of Blood on the Vessel wall)

When Urine Ouput Increases----Plasma Volume Decreases----Pressure Exerted by Column of Blood Decreases---Blood pressure decreases