Diuretics

Thiazide and thiazide-like diuretics, also called water pills, are medications that act on the kidneys’ basic unit, the nephron, to induce changes in electrolyte and water balance. They are generally used to treat mild to moderate hypertension, as well as peripheral edema. However, these medications can’t induce immediate or large volume diuresis. For this reason, they’re not typically used alone for fluid overload conditions, such as heart failure and pulmonary edema.

Okay, thiazide diuretics include chlorothiazide and hydrochlorothiazide, while examples of thiazide-like diuretics are chlorthalidone and indapamide.

Thiazide and thiazide-like diuretics can be administered orally or intravenously. Once administered, they act on the distal convoluted tubule of the nephron, which has a sodium-chloride transporter that reabsorbs sodium and chloride ions from the tubule. Thiazide and thiazide-like diuretics block this transporter, which inhibits the reabsorption of sodium and chloride ions. And since water follows sodium, more urine is produced, which reduces the body’s total fluid volume. Thiazide and thiazide-like diuretics also cause vasodilation of the arterioles, decreasing blood pressure.

Side effects of thiazide and thiazide-like diuretics mainly manifest as dehydration and electrolyte imbalance. First off, these diuretics can cause orthostatic hypotension, due to decreased circulating volume and vasodilation. They also tend to cause retention of calcium and uric acid, which can result in hypercalcemia and hyperuricemia. They can cause electrolyte imbalances like hypomagnesemia, hypochloremia, hyponatremia, as well as hypokalemia. Finally, they can alter the metabolism of glucose and fat, which may lead to hyperglycemia and hyperlipidemia.