Chlorothiazide

• The thiazides act in the distal tubule to decrease sodium reabsorption (inhibits Na/Cl transporter).

  • As a result of decreased sodium and chloride reabsorption, a hyperosmolar diuresis ensues.

  • Delivery of more sodium to the distal tubule results in potassium loss by an exchange mechanism.

• Thiazides also promote calcium reabsorption, in contrast to loop diuretics.

• The initial decrease in blood volume followed by a longer-termed reduction in vascular resistance appear to account for the hypotensive effects of the thiazides.

• Adverse Effects

  • Potassium depletion is a potentially serious side-effect that may require potassium supplementation and/or concurrent use of potassium-sparing diuretics.

  • Hyperuricemia may occur precipitating gout.

    • The increase in systemic uric acid is due to a decrease in the effectiveness of the organic acid secretory system.

  • Diabetic patient may have difficulty in maintaining proper blood sugar levels.

Category: Pharmacology Notes