Osmotic diuretic. By increasing the osmotic pressure of blood plasma and filtration in the renal glomeruli without subsequent tubular reabsorption leads to retention of water in the renal tubules and an increase in the volume of urine.Effective mannitol, mainly in the proximal tubules, although the effect is preserved to a small extent in the descending loop of the nephron and in the collecting tubes. Does not penetrate through cellular and tissue barriers (for example, blood-brain barrier), does not increase the content of residual nitrogen in the blood. Raising the osmolarity of the blood plasma, causes the fluid to move from the tissues (in particular, the eyeball, brain) to the vascular bed. Does not affect glomerular filtration. Diuresis is accompanied by a moderate increase in natriuresis without a significant effect on the excretion of potassium ions (K +). The diuretic effect is higher, the higher the concentration (dose). Ineffective in violation of the filtration function of the kidneys, as well as in the case of azotemia in patients with cirrhosis and ascites. Causes an increase in the volume of circulating blood (BCC).