From the Guidelines
Thiazide diuretics act on the Distal Convoluted Tubules (DCT).
Key Points
- Thiazides inhibit the sodium–chloride transporter in the distal convoluted tubule 1
- They are used to reduce calcium excretion in certain conditions, but their use should be carefully considered in individual cases 1
- Thiazides can lead to life-threatening hypovolemia in patients with Bartter syndrome due to compensatory salt reabsorption in the distal convoluted tubule 1
- Other diuretics that act in the distal portion of the tubule include metolazone and potassium-sparing agents, such as spironolactone 1
Mechanism of Action
- Thiazides inhibit the reabsorption of sodium or chloride at specific sites in the renal tubules, including the distal convoluted tubule 1
- This leads to increased sodium excretion and decreased physical signs of fluid retention in patients with heart failure 1
- However, thiazides can also cause hypokalemia, metabolic alkalosis, and increased potassium excretion via the channel ROMK2 to maintain electrical neutrality 1
From the Research
Diuretics Acting on the Distal Convoluted Tubules (DCT)
- Thiazide diuretics, such as hydrochlorothiazide, act on the early distal convoluted tubule by inhibiting sodium reabsorption 2, 3, 4, 5
- Thiazide-like diuretics, such as chlorthalidone and indapamide, also act on the distal convoluted tubule 5
- Potassium-sparing diuretics, including epithelial sodium channel blockers like amiloride and triamterene, act on the late distal tubule, but can also affect the distal convoluted tubule 2, 4
Mechanism of Action
- Thiazide diuretics inhibit electroneutral sodium and chloride transport by distal convoluted tubule cells, leading to increased salt and water excretion 3
- Thiazide diuretics can also stimulate potassium secretion and calcium absorption in the distal convoluted tubule 3, 6