Carbonic:
Most of the filtered sodium is reabsorbed in the proximal tubule already at cotransporter of important substances that the body wants to keep the organism. Among other things, bicarbonate completely reabsorbed by Na exchanged for hydrogen ions with the formation of carbonic acid luminal. Carbonic acid is then broken down by the enzyme kardonanhydrase in brush border with the formation of CO2 and water that is reabsorbed (see animation proximal tubule). Carbonic anhydrase will inhibit reabsorption of bicarbonate and result in reduced sodium reabsorption and alkaline diuresis. The patient will develop metabolic acidosis due to loss of bicarbonate in the urine. Carbonic used today only by special clinical problems.
Loop Diuretics (Loop Diuretics):
Operates by blocking the Na / K / 2 CL cotransportøren in thick ascending Loop of Henle (See animation ascending Loop of Henle). Here reabsorbed normally 25% of filtered Na. Loop diuretics are the most potent diuretic medicines. It is worth noting that loop diuretics will affect the osmotic gradient and thus the renal konsentreringsevne. The drugs would simultaneously inhibit absorption of calcium and magnesium in the same segment and could provide hypocalcemia and hypomagnesemia. The excretion of uric acid goes down. Increased availability of Na in the distal tubule and collecting pipes leading to increased potassium excretion and hypokalemia.
Thiazides:
Works in the distal tubule and inhibits Na reabsorption here (See animation distal tubule). As with loop diuretics thiazides may give hypokalemia by increased availability of sodium in the distal parts of the nephrons. Reabsorption of urate and calcium reabsorption increases, while magnesium excretion decreases.
Spironolactone / amiloride:
In the main cells of the manifold will aldosterone stimulation lead to increased reabsorption of Na and secretion of potassium (See animation manifold / aldosterone). Spironolactone is a aldosteronantagonistsom blocking aldosterone receptor intracellularly, while amiloride will block the luminal Na channel (ENaC) which is a consequence of aldosterone stimulation of intracellular receptor. The consequence of both increased excretion of sodium and water and reduced secretion of potassium. Both are therefore potassium-sparing diuretics unlike loop diuretics and thiazides of loss of potassium in the urine.
Tolvaptan:
Tolvaptan is a vasopressin (ADH) antagonist that counteracts the effects of ADH in manifold. Missing expression of aquaporin luminal affect the kidneys ability to concentrate urine and lead to increased excretion of free water (See animation about ADH). Tolvaptan is used exclusively by preliminary hyponatremitilstander due to SIADH (Syndrome of inapropriate production of ADH).
Mannitol:
Mannitol filtered freely, but reabsorbed to a small extent. Thus, mannitol capture water and electrolytes luminal by osmotic mechanism and working diuretic. Mannitol is currently used only in special disease states.