Mannitol Braun (Mannitol)

Mannitol is an osmotic diuretic used in several clinical situations that require rapid reduction of fluid volume in specific compartments.

• Cerebral edema: lowers intracranial pressure by osmotic dehydration of brain tissue.
• Acute renal failure with oliguria: promotes diuresis to facilitate renal clearance.
• Elevated intraocular pressure: reduces pressure during ocular surgery or acute glaucoma.
• Drug‑induced toxicity: enhances renal excretion of nephrotoxic agents such as contrast media.

• Mannitol acts as an osmotically active agent that does not readily cross cell membranes. When administered intravenously, it raises plasma osmolality, creating an osmotic gradient that pulls water from intracellular and interstitial spaces into the vascular compartment. This shift increases renal tubular flow, promotes diuresis, and reduces pressure in confined spaces such as the cranial and ocular compartments.

Mannitol injection may be associated with several adverse reactions, ranging from mild to severe.

Common Side Effects

• Headache: transient discomfort due to fluid shifts.
• Nausea or vomiting: gastrointestinal upset following infusion.
• Thirst or dry mouth: result of increased plasma osmolality.
• Electrolyte imbalance: especially hyponatremia or hypokalemia.
• Transient hypotension: due to rapid intravascular volume expansion.

Serious or Rare Side Effects

• Pulmonary edema: fluid overload in susceptible patients.
• Acute renal failure: paradoxical worsening of kidney function.
• Severe hyponatremia or hypernatremia: dangerous electrolyte disturbances.
• Anaphylactic reaction: rare hypersensitivity to the solution.
• Cardiac arrhythmia: secondary to electrolyte shifts.
• Hemolysis: in patients with G6PD deficiency.

Mannitol should be administered with careful clinical monitoring to mitigate potential risks.

• Fluid balance monitoring: assess input and output to avoid overload.
• Electrolyte surveillance: check serum sodium, potassium, and osmolality regularly.
• Pulmonary status: avoid rapid infusion in patients with existing pulmonary edema.
• Renal function: use cautiously in severe renal impairment or anuria.
• Infusion rate: do not exceed recommended rates to prevent sudden hemodynamic changes.
• Store at 2-8°C: keep refrigerated, protect from light, do not freeze or shake.

Mannitol may interact with other medications, altering efficacy or safety.

Major Interactions (Avoid)

• Loop diuretics: additive diuretic effect can cause severe electrolyte loss.
• Nephrotoxic antibiotics (e.g., aminoglycosides): increased risk of renal injury.
• Vasopressors: may exacerbate hemodynamic instability when combined.

Moderate Interactions (Monitor Closely)

• ACE inhibitors or ARBs: potential for enhanced hypotensive response.
• NSAIDs: may blunt diuretic effect and affect renal perfusion.
• Insulin: osmotic shifts can influence glucose control.
• Antiepileptic drugs: altered plasma osmolality may affect drug levels.
• Contrast media: cumulative osmotic load may increase renal stress.