• Hypersensitivity
Anaphylactic/anaphylactoid reactions, including anaphylaxis, as well as other hypersensitivity/infusion reactions have been reported with mannitol. Fatal outcome has been reported (see section 4.8).
The infusion must be stopped immediately if any signs or symptoms of a suspected hypersensitivity reaction develops. Appropriate therapeutic countermeasures must be instituted as clinically indicated.
Mannitol occurs in nature (e.g., in some fruits and vegetables) and is widely used as an excipient in drugs and cosmetics. Therefore, patients may be sensitized without having received intravenous treatment with mannitol.
• CNS toxicity
CNS toxicity manifested by, e.g. confusion, lethargy, coma has been reported in patients treated with mannitol, in particular in the presence of impaired renal function. Fatal outcomes have been reported.
CNS toxicity may result from:
- High serum mannitol concentrations
- Serum hyperosmolarity resulting in intracellular dehydration within the CNS
- Hyponatraemia or other disturbances of electrolyte and acid/base balance secondary to mannitol administration.
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 preexisting compromised blood brain barrier, the risk of increasing cerebral oedema (general or focal) associated with repeated or continued use of mannitol must be individually weighed against the expected benefits.
A rebound increase of intracranial pressure may occur several hours after the use of mannitol. Patients with compromised blood brain barrier are at increased risk.
• Risk of renal complications
Reversible, acute oligoanuric renal failure, 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 to chronic or even end-stage renal failure.
Patients with pre-existing renal disease, or those receiving potentially nephrotoxic medicinal products, are at increased risk of renal failure following administration of mannitol. Serum osmolar gap and renal function should be closely monitored and appropriate action initiated, should signs of worsening renal function or haematuria appear.
Mannitol should be administered with caution to patients with severely impaired renal function. A test dose should be employed and therapy with mannitol continued only if an adequate urine flow is achieved (see section 4.2).
If the urine output declines or haematuria is observed during mannitol infusion, the patient's clinical status should be closely reviewed for developing renal impairment, and the mannitol infusion suspended, if necessary.
• Risk of hypervolaemia
The cardiovascular status of the patient should be carefully evaluated before rapidly administering Mannitol 15% w/v.
High doses and/or high rates of infusion, as well as accumulation of mannitol (due to insufficient renal excretion of mannitol), may result in hypervolaemia, overexpansion of the extracellular fluid, which may lead to or exacerbate existing congestive heart failure.
Accumulation of mannitol may result if urine output continues to decline during administration and this may worsen existing or latent congestive heart failure.
If the patient's cardiac or pulmonary function deteriorates, treatment should be discontinued.
• Risk of water and electrolyte imbalances, hyperosmolarity
Mannitol-induced osmotic diuresis may cause or worsen dehydration/hypovolaemia and hemoconcentration. Administration of mannitol may also cause hyperosmolarity.
Should patient serum osmolarity increase during treatment, the effects of mannitol on diuresis and reduction of intracranial and intraocular pressure may be impaired.
In addition, depending on dosage and duration of administration, electrolyte and acid/base imbalances may result from transcellular shifts of water and electrolytes, osmotic diuresis and/or other mechanisms. Such imbalances may be severe and potentially fatal.
Imbalances that may result from mannitol treatment include:
• Hypernatraemia, dehydration and hemoconcentration (resulting from excessive water loss)
• Hyponatraemia (Shift of sodium-free intracellular fluid into the extra cellular compartment following mannitol infusion may lower serum sodium concentration and aggravate pre-existing hyponatraemia. Loss of sodium and potassium in the urine increases.)
Hyponatraemia can lead to headache, nausea, seizures, lethargy, coma, cerebral oedema, and death. Acute symptomatic hyponatraemic encephalopathy is considered a medical emergency.
The risk for developing hyponatraemia is increased, for example,
– in children
– in elderly patients
– in women
– postoperatively
– in persons with psychogenic polydipsia.
The risk for developing encephalopathy as a complication of hyponatraemia is increased, for example,
– in paediatric patients (≤16 years of age)
– in women (in particular, premenopausal women)
– in patients with hypoxaemia
– in patients with underlying central nervous system disease.
• Hypokalaemia
• Hyperkalaemia
• Other electrolytes imbalances
• Metabolic acidosis
• Metabolic alkalosis
By sustaining diuresis, mannitol administration may obscure and intensify inadequate hydration or hypovolaemia.
• Infusion reactions
Infusion site reactions have occurred with the use of mannitol. They include signs and symptoms of infusion site irritation and inflammation, as well as severe reactions (compartment syndrome ) when associated with extravasation. See section 4.8.
Adding other medications or using an incorrect administration technique may cause febrile reactions due to possible introduction of pyrogens. In case of an adverse reaction, infusion must be stopped immediately. For information on incompatibilities and preparation of the product and additives, please see sections 6.2 and 6.6.
• Volume and electrolyte replacement before use
In patients with shock and renal dysfunction, mannitol should not be administered until volume (fluid; blood) and electrolytes have been replaced.
• Monitoring
The acid base balance, renal function and serum osmolarity must be monitored carefully when mannitol is used.
Patients receiving mannitol should be monitored for any deterioration in renal, cardiac or pulmonary function and treatment discontinued in the case of adverse events.
Urinary output, fluid balance, central venous pressure and electrolyte balance (in particular serum sodium and potassium levels) should be carefully monitored.
• Incompatibility with blood
Mannitol should not be given concomitantly with blood because it may cause agglutination and crenation of blood cells.
• Crystallization
When exposed to low temperatures, solutions of mannitol may crystallize. Inspect for crystals prior to administration. If crystals are visible, redissolve by warming the solution up to 37°C, followed by gentle agitation. See section 4.2.
• Laboratory test interferences
Mannitol can cause false low results in some tests systems for inorganic phosphorus blood concentrations.
Mannitol produces false positive results in tests for blood ethylene glycol concentrations in which mannitol is initially oxidized to an aldehyde.
• Paediatric use
Safety and effectiveness in the paediatric population have not been established in clinical studies.
• Geriatric use
In general, dose selection for an elderly patient should be cautious, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or drug therapy.
• Risk of air embolism
Do not use plastic containers in series connections. Such use could result in air embolism due to residual air being drawn from the primary container before the administration of the fluid from the secondary container is completed.
Pressurizing intravenous solutions contained in flexible plastic containers to increase flow rates can result in air embolism if the residual air in the container is not fully evacuated prior to administration.
Use of a vented intravenous administration set with the vent in the open position could result in air embolism. Vented intravenous administration sets with the vent in the open position should not be used with flexible plastic containers.