What are the adverse effects of Mannitol?

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Last updated: March 17, 2025 • View editorial policy

From the Guidelines

Mannitol's adverse effects include fluid and electrolyte imbalances, cardiovascular effects, neurological side effects, renal complications, gastrointestinal disturbances, hypersensitivity reactions, and pulmonary edema, as reported in various studies, including 1, which highlights the risks of intravascular volume depletion, renal failure, and rebound intracranial hypertension.

Adverse Effects of Mannitol

The use of mannitol is associated with several adverse effects, including:

  • Fluid and electrolyte imbalances, such as dehydration, hyponatremia, hypokalemia, and metabolic acidosis
  • Cardiovascular effects, including hypotension, tachycardia, chest pain, and in severe cases, congestive heart failure
  • Neurological side effects, such as headache, dizziness, and seizures
  • Renal complications, including acute kidney injury, oliguria, and rebound intracranial hypertension after discontinuation
  • Gastrointestinal disturbances, like nausea, vomiting, and diarrhea
  • Hypersensitivity reactions, ranging from skin rashes to anaphylaxis
  • Pulmonary edema, particularly with rapid administration
  • Extravasation at the injection site, which may cause tissue damage and inflammation These adverse effects occur because mannitol is an osmotic diuretic that draws fluid into the vascular space, potentially causing rapid fluid shifts and electrolyte disturbances, as noted in 2 and 3.

Patient Risk Factors

Patients with cardiac or renal impairment are at higher risk for complications, and careful monitoring of fluid status, electrolytes, and renal function is essential during mannitol therapy, as emphasized in 4.

Monitoring and Management

To minimize the risk of adverse effects, it is crucial to monitor patients closely during mannitol therapy, including:

  • Fluid status and electrolyte levels
  • Renal function and urine output
  • Cardiovascular status, including blood pressure and heart rate
  • Neurological status, including signs of increased intracranial pressure or seizures By being aware of the potential adverse effects of mannitol and taking steps to monitor and manage them, healthcare providers can minimize the risks associated with this medication and optimize patient outcomes, as reported in 1, 2, 3, 4.

From the FDA Drug Label

Most common adverse reactions are pulmonary congestion, fluid and electrolyte imbalance, acidosis, electrolyte loss, dryness of mouth, thirst, marked diuresis, urinary retention, edema, headache, blurred vision, convulsions, nausea, vomiting, rhinitis, arm pain, skin necrosis, thrombophlebitis, chills, dizziness, urticaria, dehydration, hypotension, tachycardia, fever and angina-like chest pains. ( 6) The adverse effects of Mannitol include:

  • Pulmonary congestion
  • Fluid and electrolyte imbalance
  • Acidosis
  • Electrolyte loss
  • Dryness of mouth
  • Thirst
  • Marked diuresis
  • Urinary retention
  • Edema
  • Headache
  • Blurred vision
  • Convulsions
  • Nausea
  • Vomiting
  • Rhinitis
  • Arm pain
  • Skin necrosis
  • Thrombophlebitis
  • Chills
  • Dizziness
  • Urticaria
  • Dehydration
  • Hypotension
  • Tachycardia
  • Fever
  • Angina-like chest pains 5

From the Research

Adverse Effects of Mannitol

The administration of mannitol has been associated with several adverse effects, including:

  • Acute renal failure, which can occur due to the accumulation of mannitol in patients with pre-existing renal dysfunction 6, 7, 8, 9
  • Osmotic nephrosis, a condition characterized by the accumulation of mannitol in the kidneys, leading to renal damage 8
  • Renal vasoconstriction, which can occur due to high concentrations of mannitol 7
  • Cellular dehydration, which can occur due to the movement of water into the intravascular space 9
  • Congestive heart failure, which can occur due to the alteration of extracellular fluid volume and osmolality 9, 10
  • Dilutional hyponatremia with hyperosmolality, which can occur due to the accumulation of mannitol in the body 9
  • Nausea and vomiting, which can occur due to the administration of mannitol 9
  • Edema of the general body, which can occur due to the accumulation of mannitol in the body 9
  • Lethargy, which can occur due to the accumulation of mannitol in the body 9

Risk Factors for Adverse Effects

Certain risk factors can increase the likelihood of adverse effects from mannitol administration, including:

  • Pre-existing renal dysfunction 6, 7, 8, 9
  • Underlying renal compromise 7
  • Large doses or massive infusions of mannitol 7, 8
  • Patient's body habitus, age, total body water content relative to body weight, pretreatment plasma sodium concentration and plasma osmolality, and the presence of edema or ascites 10

Monitoring and Management

To minimize the risk of adverse effects, it is recommended to:

  • Monitor the osmolal gap, rather than serum osmolality alone, when using mannitol infusions 6, 7
  • Adjust the dose or discontinue mannitol if the osmolal gap increases rapidly 6
  • Use caution when administering mannitol to patients with risk factors for kidney diseases 8
  • Consider alternative treatments for patients with pre-existing renal dysfunction or underlying renal compromise 6, 7, 8, 9

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.