Clinical Question: Mannitol Use in the ED – How to dose and Where it Is Kept?
Background:
Elevated intracranial pressure (ICP > 20 mmHg) is a life-threatening disease state that can lead to brain injury caused by cerebral ischemia. The primary treatment approach includes agents that will reduce fluid in the brain and body, specifically osmotic agents like mannitol or hypertonic saline.
In addition, mannitol is an effective agent that is used to reduce intraocular pressure (IOP). It is primarily used in an emergency such as acute angle-closure glaucoma to reduce pressure in the eye.
Mannitol is an osmotic diuretic that increases osmotic pressure in the brain driving water into bloodstream leading to a reduction in intracranial pressure (ICP). It also reduces blood viscosity which helps regulate ICP. It reduces intraocular pressure by driving fluid from the eyes vitreous humor into the intravascular space.
Answer:
Mannitol 20% (20g/100mL) in 500 mL bags can be found in ED Main Pyxis, located in the Red Team.
Mannitol is primarily used at a dosing range of 0.25-2 g/kg IV over 30-60 minutes for either ICP or IOP reduction. The most common dose is 1 g/kg over 30 minutes and can be repeated every 4-6 hours as needed.
Pediatric dosing of mannitol ranges from 0.25-1 g/kg over 20-30 minutes when used for reducing ICP or IOP and can be repeated every 4-6 hours as needed also.
The effects of mannitol can be seen within 5-10 minutes and may worsen dehydration, cause rapid fluid shifts, or induce kidney injury.
Conclusion:
Mannitol is an agent in the treatment of elevated intracranial and intraocular pressure, and it is important to know where it can be located within the ED to limit delays in care.
References:
Chong SL, Zhu Y, Wang Q, et al. Clinical Outcomes of Hypertonic Saline vs Mannitol Treatment Among Children With Traumatic Brain Injury. JAMA Network Open. 2025;8(3):e250438-e250438. doi: doi.org/10.1001/jamanetworkopen.2025.0438
Karamian A, Seifi A, Lucke-Wold B. Comparing the effects of mannitol and hypertonic saline in severe traumatic brain injury patients with elevated intracranial pressure: a systematic review and meta-analysis. Neurological Research. 2024;46(9):883-892. doi: doi.org/10.1080/01616412.2024.2360862
Kim JH, Jeong H, Choo YH, et al. Optimizing Mannitol Use in Managing Increased Intracranial Pressure: A Comprehensive Review of Recent Research and Clinical Experiences. Korean Journal of Neurotrauma. 2023;19(2):162-162. doi: doi.org/10.13004/kjnt.2023.19.e25
Patel P, Patel R, Thorell W. Mannitol. Nih.gov. Published June 8, 2024. https://www.ncbi.nlm.nih.gov/books/NBK470392/
Pinto VL, Adeyinka A. Increased Intracranial Pressure. Nih.gov. Published July 6, 2025. https://www.ncbi.nlm.nih.gov/books/NBK482119/
Mariam Isa, PharmD (PGY 1 Resident) and Joanne Routsolias, ED Clinical PharmD