Mannitol is an osmotic diuretic that is primarily used to increase urine output, which reduces the amount of fluids present in the body. It works by osmosis, drawing water out of cells and into the bloodstream. When this fluid reaches the kidneys, the drug also works as a renal vasodialator, preventing the reabsorption of water and sodium along the renal tubule. Circulating freely within the tubule, mannitol retains fluid, which is converted to urine and excreted from the body. It effectively increases urine production and flushes the kidneys.
This drug is beneficial in treating acute kidney failure, glaucoma, edemas and rhabdomyolysis, and it is helpful in reducing intracranial pressure levels caused by traumatic injuries, such as hematomas. This treatment is known as mannitol osmotherapy. The results are only temporary, however, diminishing as the drug is passed out of the system. Repeated use also has diminishing results, because the cells will begin to compensate by producing idiogenic osmoles. These osmoles raise cell tonicity, limiting the osmotic flow of fluid out of the cells.
Mannitol, a monosaccharide organic compound, is a white crystalline powder that dissolves in water for administration by injection or intravenous infusion. The proper chemical name is D-mannitol (C6H14O6), and it is administered by medical professionals via injections in concentrations of 5 percent, 10 percent, 15 percent and 20 percent, as well as via intravenous infusion in a concentration of 25 percent.
By increasing urine output, this substance helps prevent kidney shutdown in cases of acute kidney failure. The drug can also reduce fluid pressure when treating glaucoma, which involves raised fluid pressure in the eye. It can also be administered to remove certain drugs and poisons from a patient’s blood system, such as aspirin, barbiturates, bromides and carbon monoxide.
When taking mannitol, regular blood tests should be performed to monitor kidney function, including potassium and sodium levels. Patients should also monitor their intake of sodium. Some possible side effects of this medication include headaches, blurred vision, chest pains, seizures, nausea, vomiting and changes in blood pressure. If any of these conditions arise, patients should contact their care provider.
Care should be taken to monitor intravascular volume. As water is drawn out of cells and into the bloodstream, the overall volume of the circulatory system will rise. Although this might lower the blood’s viscosity, improving the flow and delivery of oxygen to some parts of the body, it can also lead to high blood pressure and acute congestive heart failure.