Section 13 · Monograph
Mannitol
Reviewed Nov 2026FDA label
OsmitrolOsmotic diuretic
- Forms
- IV: 20%, 25%
- Dose
- 0.25-1g/kg IV over 20-30 min, may repeat q4-6h; keep serum osmolality below 320
- MOA
- ↑Plasma osmolality, draws water from brain tissue (↓ICP)
Indications
- Reduction of intracranial pressure and treatment of cerebral edemaFDA-labeled
- Reduction of elevated intraocular pressureFDA-labeled
Mechanism of Action
- Osmotic diuretic that raises plasma osmolality, drawing water out of brain tissue
- Also lowers blood viscosity, producing reflex cerebral vasoconstriction and ICP reduction
Full Dosing
Adult / usual
- 0.25-1g/kg IV over 20-30 minutes; may repeat every 4-6 hours
- Hold if serum osmolality exceeds 320mOsm/kg
- Use an in-line filter with 20-25% solutions (crystal formation)
Contraindications
- Anuria
- Severe pulmonary congestion or frank pulmonary edema
- Severe dehydration
- Active intracranial bleeding (except during craniotomy)
- Progressive heart failure or renal damage after mannitol
Drug Interactions
- Other diuretics increase electrolyte losses
- Nephrotoxic agents increase AKI risk
- Increases lithium excretion
Adverse Effects
- Hypovolemia and hypotension
- Hyponatremia or hypernatremia, hypokalemia
- Acute kidney injury (osmotic nephrosis)
- Rebound ICP elevation
- Pulmonary edema in heart failure
Monitoring Parameters
- Serum osmolality or osmolar gap, sodium, potassium, renal function
- Urine output and volume status
- ICP and neurologic status
Pregnancy & Lactation
- Use only if clearly needed; limited data