Mannitol
Mannitol (Osmitrol)
Mannitol
( MAN-nih-tol)
Pregnancy Category: C Osmitrol (Rx)

Classification: Diuretic, osmotic

Action/Kinetics: Increases the osmolarity of the glomerular filtrate, which decreases the reabsorption of water and increases excretion of sodium and chloride. It also increases the osmolarity of the plasma, which causes enhanced flow of water from tissues into the interstitial fluid and plasma. Thus, cerebral edema, increased ICP, and CSF volume and pressure are decreased. Onset, IV: 30-60 min for diuresis and within 15 min for reduction of cerebrospinal and intraocular pressures. Peak: 30-60 min. Duration: 6-8 hr diuresis and 4-8 hr for reduction of intraocular pressure. t 1/2: 15-100 min. Over 90% excreted through the urine unchanged. A test dose is given in clients with impaired renal function or oliguria.

Uses: Diuretic to prevent or treat the oliguric phase of acute renal failure before irreversible renal failure occurs. Decrease ICP and cerebral edema by decreasing brain mass. Decrease elevated intraocular pressure when the pressure cannot be lowered by other means. To promote urinary excretion of toxic substances. As a urinary irrigant to prevent hemolysis and hemoglobin buildup during transurethral prostatic resection or other transurethral surgical procedures. Investigational: Prevent hemolysis during cardiopulmonary bypass surgery.

Contraindications: Anuria, pulmonary edema, severe dehydration, active intracranial bleeding except during craniotomy, progressive heart failure or pulmonary congestion after mannitol therapy, progressive renal damage following mannitol therapy.

Special Concerns: Use with caution during lactation. If blood is given simultaneously with mannitol, add at least 20 mEq of sodium chloride to each liter of mannitol solution to avoid pseudoagglutination. Sudden expansion of the extracellular volume that occurs after rapid IV mannitol may lead to fulminating CHF. Mannitol may obscure and intensify inadequate hydration or hypovolemia.

Side Effects: Electrolyte: Fluid and electrolyte imbalance, acidosis, loss of electrolytes, dehydration. GI: Nausea, vomiting, dry mouth, thirst, diarrhea. CV: Edema, hypotension or hypertension, increase in heart rate, angina-like chest pain, CHF, thrombophlebitis. CNS: Dizziness, headaches, blurred vision, seizures. Miscellaneous: Pulmonary congestion, marked diuresis, rhinitis, chills, fever, urticaria, pain in arms, skin necrosis.

Laboratory Test Alterations: or Inorganic phosphorus. Ethylene glycol values because mannitol also is oxidized to an aldehyde during test.

Overdose Management: Symptoms: Increased electrolyte excretion, especially sodium, chloride, and potassium. Sodium depletion results in orthostatic tachycardia or hypotension and decreased CVP. Potassium loss can impair neuromuscular function and cause intestinal dilation and ileus. If urine flow is inadequate, pulmonary edema or water intoxication may occur. Other symptoms include hypotension, polyuria that rapidly becomes oliguria, stupor, seizures hyperosmolality, and hyponatremia. Treatment: Discontinue the infusion immediately and begin supportive measures to correct fluid and electrolyte imbalances. Hemodialysis is effective.

Drug Interactions: May cause deafness when used in combination with kanamycin.

How Supplied: Injection: 5%, 10%, 15%, 20%, 25%; Irrigation solution: 5%

Dosage
?IV Infusion Only Test dose (oliguria or reduced renal function).
Either 50 mL of a 25% solution, 75 mL of a 20% solution, or 100 mL of a 15% solution infused over 3-5 min. If urine flow is 30-50 mL/hr, therapeutic dose can be given. If urine flow does not increase, give a second test dose; if still no response, client must be reevaluated.
Prevention of acute renal failure (oliguria).
Adults: 50-100 g, as a 5%-25% solution, given at a rate to maintain urine flow of at least 30-50 mL/hr.
Treatment of oliguria.
Adults: 50-100 g of a 15%-25% solution.
Reduction of intracranial pressure and brain mass.
Adults: 1.5-2 g/kg as a 15%-25% solution, infused over 30-60 min.
Reduction of intraocular pressure.
Adults: 1.5-2 g/kg as a 20% solution (7.5-10 mL/kg) or as a 15% solution (10-13 mL/kg) given over 30-60 min. When used preoperatively, the dose should be given 1-1.5 hr before surgery to maintain the maximum effect.
Antidote to remove toxic substances.
Adults: Dose depends on the fluid requirement and urinary output. IV fluids and electrolytes are given to replace losses. If a beneficial effect is not seen after 200 g mannitol, the infusion should be discontinued.
?Irrigation Solution Urologic irrigation.
Adults: Use as a 2.5% irrigating solution for the bladder (this concentration minimizes the hemolytic effect of water alone).