Mannitol Injection: Functions, Uses, and Side Effects

Under normal circumstances, the efficacy and effects of mannitol injection include promoting drug excretion, reducing intracranial pressure, lowering intraocular pressure, treating cerebral edema, and diuresis. Side effects may include water and electrolyte disturbances, tissue damage, allergic reactions, kidney disease, thrombophlebitis, etc. A detailed analysis is as follows:

I. Efficacy and Effects

1. Promoting drug excretion: In cases of overdose of certain drugs such as sedatives, mannitol injection can be used for treatment by facilitating the excretion of drug metabolites through its osmotic effect.

2. Reducing intracranial pressure: Mannitol injection is a hyperosmolar diuretic that primarily works by increasing osmotic pressure, rapidly elevating blood osmolality, thereby dehydrating brain tissue and effectively lowering intracranial pressure.

3. Lowering intraocular pressure: Due to its small molecular size, mannitol can quickly penetrate into cells and reduce fluid content within the eye. When elevated intraocular pressure cannot be controlled with other medications, mannitol injection may be used as an adjunctive therapy to help lower eye pressure.

4. Treating cerebral edema: The main component of mannitol injection is mannitol, which is a tissue-dehydrating agent. It can be used to treat cerebral edema and edema caused by extensive burns, helping achieve effective dehydration of brain tissue.

5. Diuresis: As mannitol passes through the kidneys, it is poorly reabsorbed, leading to reduced water reabsorption and increased renal water excretion, thus producing an osmotic diuretic effect. In patients with impaired renal function presenting oliguria or anuria, mannitol injection may help reduce kidney injury and promote diuresis.

II. Side Effects

1. Water and electrolyte disturbances: Mannitol injection may lead to dilutional hyponatremia, hyperkalemia, oliguria or anuria, and cause electrolyte imbalances, including significant shifts of intracellular fluid to the extracellular space.

2. Tissue damage: If mannitol leaks into subcutaneous tissues during intravenous infusion, it may result in tissue swelling and local skin necrosis.

3. Allergic reactions: Some patients may be allergic to mannitol, experiencing symptoms such as itching, rash, urticaria, difficulty breathing, or even anaphylactic shock.

4. Kidney disease: Rapid intravenous administration of high doses may cause swelling and vacuolization of renal tubular epithelial cells, potentially leading to acute renal failure. Elderly patients with reduced renal blood flow, hyponatremia, or dehydration are more susceptible to these adverse effects.

5. Thrombophlebitis: Due to its relatively high concentration, if mannitol is infused too quickly, it may increase irritation to the veins and lead to thrombophlebitis.

It is recommended that mannitol injection be used appropriately under the guidance of a physician and should not be administered blindly.