This combination drug, containing hydrochlorothiazide (HCTZ) and triamterene, lowers blood pressure through a two-pronged approach targeting your kidneys.
HCTZ works by increasing the excretion of sodium and water from your body. This happens in the kidneys’ early part of the nephron, the distal convoluted tubule. Reducing sodium levels lessens the amount of water your body retains, consequently lowering blood volume and pressure.
Triamterene, on the other hand, acts later in the nephron, at the collecting duct. It blocks the action of aldosterone, a hormone that normally makes your kidneys reabsorb sodium and water. By preventing this reabsorption, triamterene further promotes water and sodium loss, reinforcing the blood pressure-lowering effect of HCTZ.
| Hydrochlorothiazide (HCTZ) | Inhibits sodium and chloride reabsorption | Distal convoluted tubule |
| Triamterene | Blocks aldosterone action, preventing sodium and water reabsorption | Collecting duct |
The combined effect of these two medications results in a more potent and often more effective reduction in blood pressure compared to using either drug alone. This synergistic action allows for lower individual doses, potentially reducing side effects.
