Mannitol
Also known as: Osmitrol · Resectisol · Am-Vet Mannitol · Isotol · Manniject · Osmofundin · Mannitol IV · cordycepic acid · E421 · manita · manitol · manna sugar · mannite · mannitolum · D-Mannitol
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Oliguric renal failure (not anuric) | 0.25-0.5 gram/kg IV over 5-10 minutes | IV | May repeat q4-6 hours or as CRI for first 12-24 hours | 12-24 hours | 🌎 NA |
| Oliguric renal failure (rehydrated, not fluid overloaded) | 0.25-0.5 gram/kg IV slowly over 5-10 minutes; repeat dose at 30-40 minute intervals up to 1.5 gram/kg total | IV | q30-40min | Up to 1.5 g/kg total | 🌎 NA |
| Oliguric renal failure (fluid replete) | 0.5 gram/kg IV over 20-30 minutes; if significant diuresis is accomplished within 30 minutes, may administer as a CRI of 60-120 mg/kg/hr IV or as intermittent boluses repeated every 4-6 hours | IV | CRI or q4-6h | — | 🌎 NA |
| Acute glaucoma | 0.5-1 gram/kg IV given over 15-20 minutes | IV | Single dose | — | 🌎 NA |
| Acute glaucoma (if latanoprost fails) | 1-2 grams/kg IV over a period of 20 minutes | IV | Single dose | — | 🌎 NA |
| Acute primary angle-closure glaucoma | 1 gram/kg of mannitol 20% for injection IV over 20 min | IV | May repeat in 4 hours if needed | — | 🌎 NA |
| Increased CSF pressure/cerebral edema | 0.5-1.5 grams/kg IV over 10-20 minutes | IV | q6-8h | — | 🌎 NA |
| Increased CSF pressure (critical/deteriorating patient) | 0.25 gram/kg IV bolus over 15 minutes | IV | As needed based on ICP | — | 🌎 NA |
| Cerebral edema secondary to trauma | 0.5-1 gram/kg IV followed 20 minutes later by furosemide (1 mg/kg IV) | IV | Single dose | — | 🌎 NA |
- Oliguric renal failure (not anuric): After correcting fluid, electrolyte, acid/base balance. CRI dose is 8-10% solution.
- Oliguric renal failure (fluid replete): Contraindicated in patients who are dehydrated, hypervolemic, or anuric.
- Acute glaucoma: Withhold water for 3-4 hours. IOP reduction begins in 20-30 mins.
- Acute glaucoma (if latanoprost fails): Withhold water for 1-2 hours.
- Acute primary angle-closure glaucoma: Chronic use not advised. Withhold water for several hours post-dose.
- Increased CSF pressure/cerebral edema: Limit to three boluses in a 24-hr period if possible. Monitor osmolality.
- Increased CSF pressure (critical/deteriorating patient): Equally effective as 1 g/kg but may last a shorter time.
- Cerebral edema secondary to trauma: Aggressive therapy for dying patients; potential risk for worsening hemorrhage.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Oliguric renal failure (not anuric) | 0.25-0.5 gram/kg IV over 5-10 minutes | IV | May repeat q4-6 hours or as CRI for first 12-24 hours | 12-24 hours | 🌎 NA |
| Oliguric renal failure (rehydrated, not fluid overloaded) | 0.25-0.5 gram/kg IV slowly over 5-10 minutes; repeat dose at 30-40 minute intervals up to 1.5 gram/kg total | IV | q30-40min | Up to 1.5 g/kg total | 🌎 NA |
| Oliguric renal failure (fluid replete) | 0.5 gram/kg IV over 20-30 minutes; if significant diuresis is accomplished within 30 minutes, may administer as a CRI of 60-120 mg/kg/hr IV or as intermittent boluses repeated every 4-6 hours | IV | CRI or q4-6h | — | 🌎 NA |
| Acute glaucoma | 0.5-1 gram/kg IV given over 15-20 minutes | IV | Single dose | — | 🌎 NA |
| Acute glaucoma (if latanoprost fails) | 1-2 grams/kg IV over a period of 20 minutes | IV | Single dose | — | 🌎 NA |
| Acute primary angle-closure glaucoma | 1 gram/kg of mannitol 20% for injection IV over 20 min | IV | May repeat in 4 hours if needed | — | 🌎 NA |
| Increased CSF pressure/cerebral edema | 0.5-1.5 grams/kg IV over 10-20 minutes | IV | q6-8h | — | 🌎 NA |
| Increased CSF pressure (critical/deteriorating patient) | 0.25 gram/kg IV bolus over 15 minutes | IV | As needed based on ICP | — | 🌎 NA |
| Cerebral edema secondary to trauma | 0.5-1 gram/kg IV followed 20 minutes later by furosemide (1 mg/kg IV) | IV | Single dose | — | 🌎 NA |
- Oliguric renal failure (not anuric): After correcting fluid, electrolyte, acid/base balance. CRI dose is 8-10% solution.
- Oliguric renal failure (fluid replete): Contraindicated in patients who are dehydrated, hypervolemic, or anuric.
- Acute glaucoma: Withhold water for 3-4 hours. IOP reduction begins in 20-30 mins.
- Acute glaucoma (if latanoprost fails): Withhold water for 1-2 hours.
- Acute primary angle-closure glaucoma: Chronic use not advised. Withhold water for several hours post-dose.
- Increased CSF pressure/cerebral edema: Limit to three boluses in a 24-hr period if possible. Monitor osmolality.
- Increased CSF pressure (critical/deteriorating patient): Equally effective as 1 g/kg but may last a shorter time.
- Cerebral edema secondary to trauma: Aggressive therapy for dying patients; potential risk for worsening hemorrhage.
Horses
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| General diuresis/edema | 0.25-2 gram/kg as a 20% solution by slow IV infusion | IV | Single dose | — | 🌎 NA |
| Increased intracranial pressure from traumatic brain injury (TBI) | Intermittent IV bolus doses of 0.25-1 gram/kg | IV | Intermittent | — | 🌎 NA |
- Increased intracranial pressure from traumatic brain injury (TBI): Rapid bolus administration preferred over continuous. Monitor to avoid hypovolemia.
Cattle
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Cerebral edema | 1-3 gram/kg IV | IV | Single dose | — | 🌎 NA |
| Oliguric renal failure | 1-2 gram/kg (5-10mL of 20% solution) IV | IV | Single dose | — | 🌎 NA |
- Cerebral edema: Usually given with steroids and/or DMSO.
- Oliguric renal failure: Give after rehydration; monitor urine flow and fluid balance.
Swine
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Cerebral edema | 1-3 gram/kg IV | IV | Single dose | — | 🌎 NA |
| Oliguric renal failure | 1-2 gram/kg (5-10mL of 20% solution) IV | IV | Single dose | — | 🌎 NA |
- Cerebral edema: Usually given with steroids and/or DMSO.
- Oliguric renal failure: Give after rehydration; monitor urine flow and fluid balance.
Sheep
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Cerebral edema | 1-3 gram/kg IV | IV | Single dose | — | 🌎 NA |
| Oliguric renal failure | 1-2 gram/kg (5-10mL of 20% solution) IV | IV | Single dose | — | 🌎 NA |
- Cerebral edema: Usually given with steroids and/or DMSO.
- Oliguric renal failure: Give after rehydration; monitor urine flow and fluid balance.
Goats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Cerebral edema | 1-3 gram/kg IV | IV | Single dose | — | 🌎 NA |
| Oliguric renal failure | 1-2 gram/kg (5-10mL of 20% solution) IV | IV | Single dose | — | 🌎 NA |
- Cerebral edema: Usually given with steroids and/or DMSO.
- Oliguric renal failure: Give after rehydration; monitor urine flow and fluid balance.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Mannitol is a potent osmotic diuretic primarily utilized in emergency and critical care veterinary medicine. It is a sugar alcohol that draws fluid from the intracellular to the extracellular space.
Key Indications:
- Management of acute oliguric renal failure (to promote diuresis)
- Reduction of intracranial pressure (ICP) and cerebral edema (e.g., traumatic brain injury)
- Reduction of intraocular pressure (IOP) in acute glaucoma
- Enhancement of urinary excretion of specific toxins (e.g., aspirin, barbiturates, bromides, ethylene glycol)
Clinical Pearl: Because mannitol causes rapid fluid shifts, it is highly effective but requires strict monitoring of the patient's volume and hydration status. It must be administered with an in-line filter due to its tendency to crystallize at room temperature.
Mechanism of action
Mannitol is freely filtered at the glomerulus and poorly reabsorbed in the renal tubules.
- Osmotic Diuresis: The presence of mannitol in the tubular fluid increases osmotic pressure → prevents water reabsorption → proportionately increases water excretion along with sodium, uric acid, and urea.
- Neuroprotection & ICP Reduction: Increases intravascular osmolarity → draws water from brain parenchyma across an intact blood-brain barrier (BBB) into the intravascular space → decreases cerebral edema and CSF pressure.
- Renal Protection: Dilates renal arterioles → decreases vascular resistance and blood viscosity → increases renal blood flow and glomerular filtration rate (GFR). It also minimizes renal tubular swelling and prevents the concentration of nephrotoxins in tubular fluid.
Safety & warnings
Contraindications
- Anuria secondary to renal disease
- Severe dehydration
- Severe pulmonary congestion or pulmonary edema
- Intracranial bleeding (unless during craniotomy - human label)
- Disrupted capillary membrane in the brain (can leak into interstitium and worsen edema)
- Pulmonary oedema
- Intracranial haemorrhage (relative contraindication; labelled 'use with care' but commonly used in traumatic brain injury)
Adverse effects
- Fluid and electrolyte imbalances (especially hypernatremia)
- Volume overload (if oliguria persists)
- Nausea and vomiting
- Pulmonary edema
- Congestive heart failure (CHF)
- Tachycardia
- Dizziness and headache (CNS effects)
- Circulatory overload (at high doses)
- Acidosis (at high doses)
- Thrombophlebitis
- Extravasation injury (oedema and skin necrosis)
- Diarrhoea (if administered orally)
- Acute renal failure (rare)
Precautions
Important Warnings:
- Halt therapy if progressive heart failure, pulmonary congestion, or progressive renal failure/damage (increasing oliguria/azotemia) develops.
- Hydration: Adequate fluid replacement must be administered to dehydrated animals before mannitol therapy begins. Use with caution in hypovolemic patients as it can enhance hypotension.
- Crystallization: Crystals frequently form in solutions >15%. Be certain crystals are dissolved (by warming) before administering. An in-line IV filter (5 micron) is highly recommended.
- Blood Products: Do not give with whole blood products unless at least 20 mEq/L of NaCl is added, otherwise pseudoagglutination may result.
- Glaucoma: Relatively contraindicated for treating secondary glaucomas, as it may cross the damaged blood-aqueous barrier and increase IOP.
Drug interactions
Mannitol can increase the renal elimination of lithium
Mannitol's effects on potassium and magnesium may increase the risk for QT prolongation
May exacerbate diuretic-induced hypokalaemia
Concurrent use with potassium-depleting diuretics requires caution
Nephrotoxicity has been described with concurrent use in humans
Mannitol should never be added to whole blood for transfusion or given through the same IV set
Do not add to concentrated mannitol solutions (20% or 25%) as a precipitate may form
Monitoring
- Serum electrolytes (especially sodium)
- Serum osmolality
- BUN and serum creatinine
- Urine output
- Central venous pressure (CVP), if possible
- Lung auscultation (to monitor for pulmonary edema)
- Intracranial pressure (ICP) or neurological status
- Intraocular pressure (IOP)
- Hydration status and body weight
- Serum electrolytes (especially potassium and sodium)
- Renal function (BUN, creatinine)
- Acid-base balance
Pharmacokinetics
Absorption
Administered IV in veterinary medicine. In humans, up to 17% of an oral dose is excreted unchanged in the urine.
Distribution
Distributed to the extracellular compartment. Does not penetrate the eye or the CNS unless the patient has received very high doses, is acidotic, or there is a loss of integrity of the blood-brain barrier.
Metabolism
Only 7-10% of mannitol is metabolized.
Elimination
The remainder is excreted unchanged in the urine. Elimination half-life in adult humans is ~100 minutes. Half-lives in cattle and sheep are reported to be between 40-60 minutes.
Overdose
Inadvertent overdosage can cause excessive excretion of sodium, potassium, and chloride. If urine output is inadequate, water intoxication or pulmonary edema may occur.
Treatment:
- Halt mannitol administration immediately.
- Monitor and correct electrolyte and fluid imbalances.
- Hemodialysis is effective in clearing mannitol from the bloodstream.
Available products
Formulations
- Injection: 5%, 10%, 15%, 20%, 25%
- Injectable: 10% solution (50 g/500 ml)
- Injectable: 15% solution (75 g/500 ml)
- Injectable: 20% solution (100 g/500 ml)
Veterinary
- Unapproved, veterinary-labeled products may be available.
Human-labeled
- Mannitol Injection: 5% (50 mg/mL), 10% (100 mg/mL), 15% (150 mg/mL), 20% (200 mg/mL), 25% (250 mg/mL)
- Mannitol Solution: 5 grams/100 mL
- Mannitol 10% IV infusion
- Mannitol 15% IV infusion
- Mannitol 20% IV infusion
Regulatory status
Available as POM (Prescription Only Medicine).
Available as POM-V.
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store at room temperature; avoid freezing. Crystallization may occur at low temperatures in concentrations greater than 15%. Resolubilize crystals by heating the bottle in hot water (up to 80°C) and cool to body temperature before administering. An in-line IV filter (5 micron) is highly recommended when administering concentrated solutions.
Client information
Mannitol is an emergency medication that must be administered by professional veterinary staff in a hospital setting where adequate monitoring can occur.
Because it causes rapid shifts of fluid within the body, your pet's hydration status, electrolytes, and urine output will be closely monitored to ensure safety and effectiveness.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.