What Is Mannitol?

Mannitol is an osmotic diuretic — a sugar alcohol used primarily in hospital settings to reduce dangerously elevated intracranial pressure (brain swelling) and intraocular pressure (eye pressure). It is administered intravenously under the brand name Osmitrol.

Mannitol is also available as an inhaled formulation (Bronchitol) for add-on maintenance treatment of cystic fibrosis, where it helps hydrate airway secretions and improve lung function. Another inhaled form (Aridol) is used diagnostically to test for bronchial hyperresponsiveness.

Common off-label uses include promoting diuresis in acute kidney injury, flushing toxic substances from the body, and priming heart-lung bypass machines during cardiac surgery.

How Does Mannitol Work?

Mannitol is a 6-carbon sugar alcohol that acts as an osmotic agent. When given intravenously, it increases the osmolality of blood plasma, creating an osmotic gradient that draws water out of tissues — particularly the brain and eyes — and into the bloodstream.

In the kidneys, Mannitol is freely filtered by the glomerulus but is poorly reabsorbed by the renal tubules. This means it pulls water into the urine, producing a powerful diuretic effect. This mechanism helps reduce cerebral edema, lower intraocular pressure, and promote the excretion of toxic substances.

When inhaled (as Bronchitol), Mannitol works by drawing water into the airway surface, hydrating thick mucus secretions and making them easier to clear from the lungs.

What Doses Are Available for Mannitol?

• Mannitol 5% IV Solution
• Mannitol 10% IV Solution
• Mannitol 15% IV Solution
• Mannitol 20% IV Solution (most commonly used)
• Mannitol 25% IV Solution
• Bronchitol 40 mg Inhalation Capsules (for cystic fibrosis)
• Aridol Bronchial Challenge Test Kit (for bronchial hyperresponsiveness testing)
• Mannitol-Sorbitol Irrigation Solution (for urological procedures)

How Hard Is It to Find Mannitol in Stock?

Mannitol currently has a findability score of 40 out of 100, meaning it is moderately difficult to find. ICU Medical's Mannitol 20% premixed IV bags (250 mL and 500 mL) are on active allocation per the ASHP drug shortage list. This shortage has been ongoing since 2023 as part of broader IV fluid supply chain disruptions.

Hospitals and pharmacies may experience localized stockouts, especially for the 20% concentration premixed bags. If your facility is having trouble sourcing Mannitol, Medfinder can help you locate it in stock nearby.

Who Can Prescribe Mannitol?

Because Mannitol IV is primarily a hospital medication, it is most commonly ordered by:

• Neurosurgeons and Neurologists — for reducing intracranial pressure
• Emergency Medicine Physicians — for acute brain swelling and trauma
• Critical Care / ICU Physicians — for managing cerebral edema in critically ill patients
• Ophthalmologists — for reducing intraocular pressure
• Nephrologists — for promoting diuresis in kidney injury
• Anesthesiologists and Trauma Surgeons — during surgical procedures
• Pulmonologists — for prescribing Bronchitol to cystic fibrosis patients

Is Mannitol a Controlled Substance?

No. Mannitol is not a controlled substance and has no DEA scheduling. It does not have abuse potential. It is a standard hospital medication available by prescription and is typically administered by healthcare professionals in clinical settings.

Common Side Effects of Mannitol

• Headache
• Nausea and vomiting
• Dizziness
• Thirst and dry mouth
• Frequent urination (diuresis)
• Electrolyte imbalances (low sodium, high potassium)
• Dehydration
• Blurred vision
• Chills
• Injection site reactions

Serious side effects may include acute kidney injury, severe electrolyte disturbances, pulmonary edema, seizures, and anaphylaxis. Mannitol must be administered under medical supervision with monitoring of serum osmolality and kidney function.

Alternative Medications to Mannitol

If Mannitol is unavailable due to the current shortage, your healthcare provider may consider these alternatives:

• Hypertonic Saline (3%, 7.5%, 23.4%) — Increasingly used as a first-line alternative for reducing intracranial pressure. Some studies suggest it may be equally or more effective than Mannitol, and it does not cause osmotic diuresis.
• Furosemide (Lasix) — A loop diuretic sometimes used alongside or instead of Mannitol for reducing intracranial pressure and promoting diuresis.
• Glycerol (Glycerin) — Another osmotic agent that can be given orally or IV to reduce intracranial or intraocular pressure. Less commonly used but may be an option when Mannitol is unavailable.
• Acetazolamide (Diamox) — A carbonic anhydrase inhibitor used to reduce intraocular pressure and sometimes intracranial pressure. Available as oral tablets and IV injection.

Drug Interactions with Mannitol

Mannitol can interact with several medications. Always inform your healthcare team about all medications being administered:

• Nephrotoxic drugs (Aminoglycosides, Cisplatin, NSAIDs, Cyclosporine) — Increased risk of kidney damage when combined with Mannitol
• Other diuretics (Furosemide, Hydrochlorothiazide) — Enhanced diuretic effect with risk of severe dehydration and dangerous electrolyte imbalances
• Digoxin — Mannitol-induced low potassium may increase Digoxin toxicity
• Lithium — Mannitol increases renal Lithium clearance, potentially making Lithium less effective
• Neurotoxic drugs — Mannitol may allow increased drug penetration through the blood-brain barrier, potentiating CNS toxicity
• ACE Inhibitors and ARBs — Additive risk of renal impairment

Final Thoughts on Mannitol

Mannitol remains a critical hospital medication for managing life-threatening conditions like cerebral edema and elevated intracranial pressure. Unfortunately, the ongoing IV fluid supply chain disruptions have kept Mannitol premixed bags on allocation since 2023, making it challenging for some facilities to maintain adequate stock.

If your hospital or pharmacy is struggling to find Mannitol in stock, Medfinder can help you locate available supply nearby. For patients prescribed Bronchitol for cystic fibrosis, the Chiesi CareConnect program may help with access and affordability.

Always work closely with your healthcare provider to ensure continuity of care, especially during shortage periods when alternative therapies like Hypertonic Saline or Furosemide may need to be considered.