How do diuretics treat hypercalcemia?
Loop diuretics inhibit the Na-K-2Cl transporter and also increase calcium excretion. They are often used in the treatment of hypercalcemia. Thiazide diuretics block the thiazide-sensitive NaCl transporter in the distal convoluted tubule, and can decrease calcium excretion.
What is the mechanism of action of K sparing diuretics?
Mechanism of Action: A potassium-sparing diuretic that inhibits sodium, potassium, ATPase. Interferes with sodium and potassium exchange in distal tubule, cortical collecting tubule, and collecting duct. Increases sodium and decreases potassium excretion. Also increases magnesium, decreases calcium loss.
What is the mechanism of diuretics?
Mechanisms of diuretic drugs. Diuretic drugs increase urine output by the kidney (i.e., promote diuresis). This is accomplished by altering how the kidney handles sodium. If the kidney excretes more sodium, then water excretion will also increase.
What do diuretics do to calcium?
Generally, by increasing sodium and water excretion, diuretics will cause a concomitant increase in calcium excretion. As they diminish blood volume and alter renal hemodynamics, diuretics enhance calcium reabsorption in the proximal tubule, modulating their usual effects on calcium excretion.
Why do diuretics cause hypercalcemia?
Thiazide diuretics can increase renal tubular reabsorption of calcium, resulting in hypercalcemia. However, thiazide-associated hypercalcemia also can represent unmasking of preexisting primary hyperparathyroidism (PHPT) or incidental development of PHPT during thiazide therapy.
How do thiazide diuretics cause hyperuricemia?
Thiazide diuretics are associated with elevated serum uric acid (SUA) levels. They increase direct urate reabsorption in the proximal renal tubules [3]. Elevated SUA is an independent risk factor for gout [2]. These agents increase the levels of SUA and thus may contribute to the risk of gout.
Which potassium-sparing diuretics inhibits the action of aldosterone?
Triamterene is a potassium-sparing diuretic that acts in the distal convoluted tubule independently of the action of aldosterone, inhibiting sodium channels (1).
What is the mechanism of action of amiloride?
Amiloride works by inhibiting sodium reabsorption in the distal convoluted tubules and collecting ducts in the kidneys by binding to the amiloride-sensitive sodium channels. This promotes the loss of sodium and water from the body, but without depleting potassium.
Why do diuretics inhibit sodium reabsorption?
They directly inhibit Na+ reabsorption by the thick ascending limb of Henle’s loop by blocking the Na+-K+-2Cl− symporter located in the apical membrane of these cells (see Chapter 4). By this action, they not only inhibit Na+ reabsorption but also disrupt the ability of the kidneys to dilute and concentrate the urine.
Why do thiazide diuretics decrease calcium excretion?
By increasing calcium reabsorption from the luminal membrane into the interstitium in exchange for sodium, thiazides reduce urine calcium levels and increase blood calcium.
Which diuretic promotes calcium reabsorption?
The major effect of thiazide diuretic administration is to reduce calcium excretion via increased tubular calcium reabsorption in the distal tubule. In a study of corticosteroid-treated patients, 50 mg of hydrochlorothiazide given twice daily also increased intestinal calcium absorption [65].
What are calcium-sparing diuretics?
12. Calcium-sparing diuretics Agents that result in a relatively low rate of excretion of calcium. The thiazides and potassium-sparing diuretics are considered to be calcium-sparing diuretics. The thiazides cause a net decrease in calcium lost in urine.
What is the mechanism of action of potassium sparing diuretics?
Potassium-sparing diuretics Amiloride, triamterene, and the spirolactones are potassium-sparing diuretics which act on the distal parts of the nephron, from the late distal tubule to the collecting duct. In these segments, active sodium reabsorption occurs through the following mechanism: sodium ions enter the cell through spe …
What is the effect of calcium sparing on calcium in urine?
The reduced concentration of calcium in the urine can lead to an increased rate of calcium in serum. The sparing effect on calcium can be beneficial in hypocalcemia, or unwanted in hypercalcemia . The thiazides and potassium-sparing diuretics are considered to be calcium-sparing diuretics.
Do loop diuretics increase or decrease calcium excretion?
The thiazides cause a net decrease in calcium lost in urine. The potassium-sparing diuretics cause a net increase in calcium lost in urine, but the increase is much smaller than the increase associated with other diuretic classes. By contrast, loop diuretics promote a significant increase in calcium excretion.
