Mannitol is a 6-carbon sugar alcohol.
Occurs naturally in fruits and vegetables, and is metabolically inert in humans.
An osmotic diuretic.
Each mL contains: Mannitol 250 mg; Water for Injection.
The osmolar concentration is 1372 mOsmol/L.
The pH of a 5% solution is between 4.5 and 7.0.
After intravenous injection it is confined to the extracellular space, metabolized only slightly and excreted rapidly by the kidneys, with 80% of the dose appearing in the urine in three hours.
Freely filtered by the glomeruli with less than 10% tubular reabsorption.
It is not secreted by tubular cells and induces diuresis by elevating the osmolarity of the glomerular filtrate and thereby hinders tubular reabsorption of water.
As a result urinary output of water and the excretion of sodium and chloride are enhanced.
Poorly absorbed from the gastrointestinal tract.
Is used in urology as a nonhemolytic irrigant.
Mannitol Injection is indicated for: promotion of diuresis, in the prevention and/or treatment of the oliguric phase of acute renal failure before irreversible renal failure becomes established, the reduction of intracranial pressure and treatment of cerebral edema by reducing brain mass, reduction of elevated intraocular pressure when it cannot be lowered by other means, promotion of urinary excretion of toxic substances, and Mannitol solution, 2.5% is indicated as an irrigation solution in transurethral prostatic resection or other transurethral surgical procedures.
Contraindications include: established anuria due to severe renal disease, severe pulmonary congestion or frank pulmonary edema, intracranial bleeding, severe dehydration, increasing renal damage or dysfunction after institution of mannitol therapy, and increasing heart failure or pulmonary congestion after therapy is started.
In severe impairment of renal function a test dose should be given.
Complications include excessive loss of water and electrolytes, and careful monitoring of renal function, serum sodium and potassium is required during mannitol therapy.
Use may increase preexisting hemoconcentration and hypernatremia.
Shift of sodium-free intracellular fluid into the extracellular compartment after mannitol infusion may lower serum sodium concentration and aggravate preexisting hyponatremia.
Urine output must be monitored and the mannitol infusion promptly discontinued if output is low.
Inadequate urine output results in accumulation of mannitol, expansion of extracellular fluid volume and could result in water intoxication or congestive heart failure.
Must be used with caution in patients with significant cardiopulmonary or renal dysfunction.
Irrigating solutions used in transurethral prostatectomy may enter the systemic circulation and exert a systemic effect and may significantly alter cardiopulmonary and renal dynamics.
Adverse reactions are infrequent but may include: fluid and electrolyte imbalance, acidosis, dehydration, dryness of mouth, nausea, vomiting, diarrhea, osmotic nephrosis, urinary retention, headaches, dizziness, seizures, blurred vision, fluid excess with edema, pulmonary edema, hypotension, hypertension, tachycardia, angina, skin necrosis, thrombophlebitis, urticaria, and thirst.
The adult dosage ranges from 50 to 200 g in 24 hours.
In most instances an adequate response will be achieved at a dosage of approximately 100 g in 24 hours.
In the presence of oliguria or inadequate renal function a test dose should be given.
The test dose may be approximately 0.2 g/kg which is about 50 mL of a 25% solution infused in three to five minutes to produce an adequate urine flow.
A second test dose may be tried if urine does not increase within two or three hours.
May be used to prevent acute renal failure from surgery, postoperatively, following trauma, or suspected or actual transfusion reaction, by giving 50-100g as a 5-25% solution.
For the treatment of oliguria is 50 to 100 g as a 15 to 25% solution can be given.
To reduce elevated intracranial pressure, cerebral edema or elevated intraocular pressure a 25% solution is recommended to create intravascular hyperosmolarity with a 1.5-2.g/kg dose infusion over 30-60 minutes.
For urinary irrigation a 2.5% solution is used to minimizes the hemolytic effect of water irrigation alone.