Pharmacology Chapter 15

Front 1

MECHANISM
Carbonic Anhydrase Inhibitors

Back 1

The mechanism of action is inhibition of carbonic anhydrase in the brush border and cytoplasm

Front 2

MECHANISM
Loop Diuretics

Back 2

Loop diuretics inhibit the cotransport of sodium, potassium, and chloride (NKCC2

Front 3

MECHANISM
Thiazide Diuretics

Back 3

The major action of thiazides is to inhibit sodium chloride transport in the early segment of the distal convoluted tubule

Front 4

MECHANISM
Potassium-Sparing Diuretics

Back 4

Spironolactone and eplerenone are steroid derivatives and act as pharmacologic antagonists of aldosterone in the collecting tubules. By combining with and blocking the intracellular aldosterone receptor, these drugs reduce the expression of genes controlling synthesis of epithelial sodium ion channels (ENaC) and Na+/K+ ATPase. Amiloride and triamterene act by blocking the epithelial sodium channels in the same portion of the nephron

Front 5

MECHANISM
Osmotic Diuretics

Back 5

Because it is freely filtered at the glomerulus but poorly reabsorbed from the tubule, mannitol remains in the lumen and "holds" water by virtue of its osmotic effect. The major location for this action is the proximal convoluted tubule, where the bulk of isosmotic reabsorption normally occur

Front 6

Antidiuretic Hormone Agonists
Antidiuretic hormone (ADH) and desmopressin are prototypical ADH agonists

Back 6

ADH and desmopressin reduce urine volume and increase its concentration. ADH and desmopressin are useful in pituitary diabetes insipidus

Front 7

Antidiuretic Hormone Antagonists

Back 7

ADH antagonists oppose the actions of ADH and other naturally occurring peptides that act on the same V2 receptor. Such peptides are produced by certain tumors (eg, small cell carcinoma of the lung) and can cause significant water retention and dangerous hyponatremia. This syndrome of inappropriate ADH secretion (SIADH) can be treated with demeclocycline and conivaptan