5 WARNINGS AND PRECAUTIONS5.1 Hypersensitivity ReactionsSerious hypersensitivity reactions, including anaphylaxis, hypotension, and dyspnea resulting in cardiac arrest and death have been reported with Mannitol Injection [see Adverse Reactions (6)]. Stop the infusion immediately if signs or symptoms of a suspected hypersensitivity reaction develop. Initiate appropriate therapeutic countermeasures as clinically indicated.5.2 Renal Complications Including Renal FailureRenal complications, including irreversible renal failure, have been reported in patients receiving mannitol.Reversible, oliguric acute kidney injury has occurred in patients with normal pretreatment renal function who received large intravenous doses of mannitol. Although the osmotic nephrosis associated with mannitol administration is in principle reversible, osmotic nephrosis in general is known to potentially proceed chronic or even end-stage renal failure. Monitor renal function closely, including signs of urine output reduction, during mannitol injection.Patients with pre-existing renal disease, patients with conditions that put them at risk for renal failure, or those receiving potentially nephrotoxic drugs or other diuretics, are at increased risk for renal failure following administration of Mannitol Injection. Avoid concomitant administration of nephrotoxic drugs (e.g., aminoglycosides) or other diuretics with Mannitol Injection, if possible [see Drug Interactions (7)].Patients with oliguric acute kidney injury who subsequently develop anuria while receiving mannitol are at risk of congestive heart failure, pulmonary edema, hypertensive crisis, coma, and death.During and following infusion of Mannitol Injection for the reduction in intracranial pressure, monitor the patient clinically and laboratory tests for changes in fluid and electrolyte status. Discontinue Mannitol Injection if renal function worsens [see Warnings and Precautions (5.5)].5.3 Central Nervous System (CNS) ToxicityCNS toxicity manifested by, e.g., confusion, lethargy, coma, has been reported in patients treated with mannitol, some resulting in death, in particular in the presence of impaired renal function CNS toxicity may result from high serum mannitol concentrations, serum hyperosmolarity resulting in intracellular dehydration within CNS, hyponatremia or other disturbances of electrolyte and acid/base balance secondary to mannitol administration [see Warnings and Precautions (5.4)].At high concentrations, mannitol may cross the blood brain barrier and interfere with the ability of the brain to maintain the pH of the cerebrospinal fluid especially in the presence of acidosis.In patients with pre-existing compromise of the blood brain barrier, the risk of increasing cerebral edema (general and focal) associated with repeated or continued use of Mannitol Injection must be individually weighed against the expected benefits.A rebound increase of intracranial pressure may occur several hours after the infusion. Patients with a compromised blood brain barrier are at increased risk.Concomitant administration of neurotoxic drugs (e.g., aminoglycosides) with Mannitol Injection may potentiate neurotoxicity. Avoid concomitant use of neurotoxic drugs, if possible [see Drug Interactions (7.3)].During and following infusion of Mannitol Injection for the reduction in intracranial pressure, monitor the patient clinically and laboratory tests for changes in fluid and electrolyte status. Discontinue Mannitol Injection if CNS toxicity develops [see Warnings and Precautions (5.5)].5.4 Fluid and Electrolyte Imbalances, HyperosmolarityDepending on dosage and duration, administration of Mannitol Injection may result in hypervolemia leading to or exacerbating existing congestive heart failure. Accumulation of mannitol due to insufficient renal excretion increases the risk of hypervolemia. Mannitol-induced osmotic diuresis may cause or worsen dehydration/hypovolemia and hemoconcentration. Administration of Mannitol Injection may also cause hyperosmolarity [see Description (11)].Depending on dosage and duration of administration, electrolyte and acid/base imbalances may also result from transcellular shifts in water and electrolytes, osmotic diuresis, and/or other mechanisms. Such imbalances may be severe and potentially fatal.Imbalances that may result from administration of Mannitol Injection include:Hypernatremia, dehydration, and hemoconcentrationHyponatremia, which can lead to headache, nausea, seizures, lethargy, coma, cerebral edema, and death. Acute symptomatic hyponatremic encephalopathy is considered a medical emergency.Hypo/hyperkalemia. The development of electrolyte imbalances (e.g., hyperkalemia, hypokalemia) associated with mannitol administration may result in cardiac adverse reactions in patients receiving drugs that are sensitive to such imbalances (e.g., digoxin, agents that may cause QT prolongation, neuromuscular blocking agents) [see Drug Interactions (7.4)].Other electrolyte disturbancesMetabolic acidosis/alkalosisPediatric patients less than two years of age, particularly preterm and term neonates, may be at higher risk for fluid and electrolyte abnormalities following administration of Mannitol Injection due to decreased glomerular filtration rate and limited ability to concentrate urine [see Use in Specific Populations (8.4)].During and following infusion of Mannitol Injection for the reduction in intracranial pressure, monitor fluid and electrolyte status and discontinue Mannitol Injection if imbalances occur [see Warnings and Precautions (5.5)].5.5 Monitoring/Laboratory TestsDuring and following infusion of Mannitol Injection for the reduction in intracranial pressure, monitor:serum osmolarity, serum electrolytes (including sodium, potassium, calcium and phosphate) and acid/base balance,the osmol gapsigns of hypo- or hypervolemia, including urine outputrenal, cardiac, and pulmonary functionintracranial pressureDiscontinue Mannitol Injection if renal, cardiac, or pulmonary status worsens or CNS toxicity develops [see Contraindications (4)].5.6 Infusion Site ReactionsThe infusion of hypertonic solutions through a peripheral vein, including Mannitol Injection, may result in peripheral venous irritation, including phlebitis. Other severe infusion site reactions, such as compartment syndrome and swelling associated with extravasation, can occur with administration of Mannitol Injection [see Adverse Reactions (6)]. Mannitol Injection is preferably administered through a central venous catheter [see Dosage and Administration (2.1)].5.7 Interference with Laboratory TestsHigh concentrations of mannitol can cause false low results for inorganic phosphorus blood concentrations [see Drug Interactions (7.6)].Mannitol may produce false positive results in tests for blood ethylene glycol concentrations [see Drug Interactions (7.6)].