Chlorthiazide | Structure | Mode of Action

Chlorthiazide is a thiazide diuretic used to treat hypertension and edema by promoting sodium and water excretion through the kidneys.

Chlorthiazide is a sulfonamide derivative belonging to the thiazide diuretic class, characterized by a benzothiadiazine structure with chlorine substituents.
Chemical Formula: C₇H₇ClN₃O₄S₂

Thiazide Receptor Blocking: Inhibits the sodium-chloride symporter in the distal convoluted tubule of the nephron.
Sodium and Chloride Excretion: Promotes excretion of sodium and chloride ions, leading to increased water loss (diuresis).
Potassium Loss: Causes increased excretion of potassium and hydrogen ions, potentially leading to hypokalemia and metabolic alkalosis.

Hypertension: First-line therapy for essential hypertension by reducing blood volume and vascular resistance.
Edema: Manages edema associated with congestive heart failure, liver cirrhosis, and renal disease.
Nephrolithiasis Prevention: Helps prevent the formation of calcium-containing kidney stones.
Heart Failure: Used as part of diuretic therapy to manage fluid retention.

Benzothiadiazine Core: Essential for thiazide diuretic activity by targeting the sodium-chloride symporter.
Chlorine Substituents: Enhance binding affinity and potency by increasing lipophilicity and facilitating interaction with the transporter.
Sulfonamide Group: Critical for inhibition of the sodium-chloride symporter; substitutions can affect potency and duration of action.
Substituents on the Benzene Ring: Influence pharmacokinetics, including solubility and bioavailability.