mannitol
Osmitrol, Resectisol

Available forms
Available by prescription only
Injection: 5%, 10%, 15%, 20%, 25%
Urogenital solution: 5 g/100 ml distilled water

Indications and dosages
 Test dose for marked oliguria or suspected inadequate renal function. Adults and children older than age 12: 200 mg/kg or 12.5 g as a 15% or 20% solution I.V. over 3 to 5 minutes. Response is adequate if 30 to 50 ml urine/hour is excreted over 2 to 3 hours. May repeat test dose one time if response is inadequate the first time.
Children age 12 and younger ◇: 0.2 g/kg or 6 g/m² I.V. over 3 to 5 minutes.
 Treatment of oliguria. Adults and children older than age 12: 50 to 100 g as a 15% to 20% solution I.V. over 90 minutes to several hours.
Children age 12 and younger: 2 g/kg or 60 g/m² I.V.
 Prevention of oliguria or acute renal failure. Adults and children older than age 12: 50 to 100 g followed by a 5% to 10% solution I.V. Exact level is determined by fluid requirements.
 Treatment of edema and ascites. Adults and children older than age 12: 100 g as a 10% to 20% solution I.V. over 2 to 6 hours.
Children age 12 and younger ◇: 2 g/kg or 60 g/m² I.V. as a 15% to 20% solution over 2 to 6 hours.
 To reduce intraocular pressure or intracranial pressure. Adults and children older than age 12: 1.5 to 2 g/kg as a 15% to 25% solution I.V. over 30 to 60 minutes (60 to 90 minutes before surgery if used preoperatively).
Children age 12 and younger ◇: 2 g/kg or 60 g/m² I.V. as a 15% to 20% solution over 30 to 60 minutes.
 To promote diuresis in drug intoxication. Adults and children older than age 12: 25 g loading dose followed by an infusion maintaining 100 to 500 ml urine output/hour and positive fluid balance (of 1 to 2 L). For patients with barbiturate poisoning, give 0.5 g/kg followed by a 5% to 10% solution. Or, 1 L of 10% solution during first hour. Subsequent dosing based on urine output, urine pH, and fluid balance.
Children age 12 and younger ◇: 2 g/kg or 60 g/m² of 5% to 10% solution as needed.
 Urologic irrigation. Adults: 2.5% to 5% irrigating solution via indwelling urethral catheter.

Pharmacodynamics
Diuretic action: Mannitol increases the osmotic pressure of glomerular filtrate, inhibiting tubular reabsorption of water and electrolytes, thus promoting diuresis. This action also promotes urinary elimination of certain drugs. This effect is useful for prevention and management of acute renal failure or oliguria. This action is also useful for reduction of intracranial or intraocular pressure because mannitol elevates plasma osmolality, enhancing flow of water into extracellular fluid.

Pharmacokinetics
Absorption: Administered I.V.
Distribution: Remains in the extracellular compartment. It doesn’t cross the blood-brain barrier.
Metabolism: Metabolized minimally to glycogen in the liver.
Excretion: Filtered by the glomeruli; half-life in adults with normal renal function is about 100 minutes.

Contraindications and precautions
Contraindicated in patients hypersensitive to drug and in those with anuria, severe pulmonary congestion, frank pulmonary edema, severe heart failure, severe dehydration, metabolic edema, progressive renal disease or dysfunction, or active intracranial bleeding except during craniotomy. Use cautiously in pregnant women.

Interactions
Drug-drug. Cardiac glycosides: May enhance the possibility of digitalis toxicity. Monitor serum digoxin levels.
Diuretics, including carbonic anhydrase inhibitors: Increases effects of these drugs. Monitor patient closely.
Lithium: Enhances renal excretion of lithium and lowers serum lithium levels. Monitor lithium levels.

Adverse reactions
CNS: seizures, dizziness, headache, local pain, fever.
CV: edema, thrombophlebitis, hypotension, hypertension, heart failure, tachycardia, angina-like chest pain.
EENT: blurred vision, rhinitis.
GI: thirst, dry mouth, nausea, vomiting, diarrhea.
GU: urine retention.
Metabolic: fluid and electrolyte imbalance, dehydration.
Skin: urticaria.
Other: chills.

Effects on lab test results
• May increase or decrease calcium and potassium levels.

Overdose and treatment
Signs and symptoms of overdose include polyuria, cellular dehydration, hypotension, and CV collapse.
 Discontinue infusion and institute supportive measures. Hemodialysis removes mannitol and decreases serum osmolality.

Special considerations
• Use with extreme caution in patients with compromised renal function; monitor vital signs (including CVP) hourly. Monitor input and output, weight, renal function, fluid balance, and serum and urine sodium and potassium levels daily.
• For maximum pressure reduction during surgery, give drug 1 to 11/2 hours preoperatively.
• Give drug I.V. via an in-line filter with great care to avoid extravasation.
• Don’t give with whole blood; agglutination will occur.
• Mannitol solutions commonly crystallize at low temperatures; place crystallized solutions in a hot water bath, shake vigorously to dissolve crystals, and cool to body temperature before use. Don’t use solutions with undissolved crystals.
• Don’t give more than 1 L of fluids in excess of urine output daily.
• Store drug at 59° to 86° F (15° to 30° C) and protect from freezing.
Breast-feeding patients
• Safety of drug in breast-feeding women hasn’t been established.
Pediatric patients
• Dosage for children younger than age 12 hasn’t been established.
Geriatric patients
• Geriatric or debilitated patients need close observation and possibly lower dosages. Excessive diuresis promotes rapid dehydration, leading to hypovolemia, hypokalemia, and hyponatremia.

Patient education
• Tell patient that he may feel thirsty or have a dry mouth; emphasize importance of drinking only the amount of fluids provided.
• With initial doses, warn patient to change positions slowly, especially when rising from lying or sitting position, to prevent dizziness from orthostatic hypotension.
• Instruct patient to immediately report shortness of breath, apnea, or pain in the chest, back, or legs.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use