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Osmotic Diuretic/Prescription

OSMITROL 20% IN WATER IN PLASTIC CONTAINER

OSMITROL 20% IN WATER IN PLASTIC CONTAINER

Clinical safety rating

caution

Comprehensive clinical and safety monograph for OSMITROL 20% IN WATER IN PLASTIC CONTAINER (OSMITROL 20% IN WATER IN PLASTIC CONTAINER).


Mechanism of Action

Osmotic diuretic that increases plasma osmolality, drawing water from intracellular spaces into extracellular fluid and increasing renal tubular osmotic pressure, thereby inhibiting water reabsorption and promoting diuresis.

What the body does with it

MetabolismNot significantly metabolized; excreted unchanged by the kidneys via glomerular filtration.
ExcretionPrimarily renal (90-100% unchanged) via glomerular filtration; <3% metabolized in liver; minimal biliary/fecal excretion.
Half-lifeTerminal elimination half-life is 0.25–1.5 hours in normal renal function; prolonged to 4–6 hours with anuria or oliguria. Clinically, osmotic diuresis lasts as long as urine output sustains concentration.
Protein bindingApproximately 0%; no significant protein binding.
Volume of Distribution0.3–0.6 L/kg; distributes primarily in extracellular fluid, limited intracellular penetration. Higher Vd in edema states.
BioavailabilityIntravenous: 100% (only route of administration); oral bioavailability is negligible due to poor absorption and osmotic diarrhea.
Onset of ActionIntravenous: diuresis occurs within 1–3 hours of infusion; reduction of intracranial pressure begins within 15–45 minutes.
Duration of ActionDiuresis lasts 1–3 hours post-infusion; reduction of cerebral edema persists for 3–8 hours, depending on dose and renal function. Repeated doses may be needed.
Molecular Weight182.17

Classification & Brands

Dosing & administration

0.25-1 g/kg intravenously over 30-60 minutes, repeated every 6-12 hours if needed.

Dosage formINJECTABLE
Renal impairmentContraindicated in anuria; for oliguria, monitor urine output closely; no specific GFR-based dose adjustment established, but use with caution in renal impairment.
Liver impairmentNo specific Child-Pugh based adjustment; use with caution in hepatic failure.
Pediatric use0.25-1 g/kg intravenously over 30-60 minutes, repeat every 4-6 hours as needed; maximum 2 g/kg/day.
Geriatric useStart at lower end of dosing range (0.25 g/kg) due to decreased renal function; monitor electrolytes and renal function closely.

Use during pregnancy

1st trimesterContraindicated in first trimester due to risk of fetal hypernatremia and dehydration.
2nd trimesterUse only if clearly needed; may cause maternal fluid shifts affecting placental perfusion.
3rd trimesterAvoid; may induce maternal hypervolemia and electrolyte disturbances in neonate.

Clinical note

Comprehensive clinical and safety monograph for OSMITROL 20% IN WATER IN PLASTIC CONTAINER (OSMITROL 20% IN WATER IN PLASTIC CONTAINER).

Placental transferOsmotically active; crosses placenta to some extent, causing fetal shifting of water and electrolytes.
BreastfeedingNot recommended during breastfeeding; excretion in milk unknown but potential for infant hypernatremia and diuresis.
Lactation RatingL5
Teratogenic RiskPregnancy Category C. Animal reproduction studies have not been conducted. Osmotic diuretics may cause maternal dehydration and electrolyte imbalances. Inadequate human data across all trimesters; potential fetal harm if maternal hypovolemia or severe electrolyte disturbances occur. Use only if clearly needed.
Fetal MonitoringMonitor maternal urine output, serum electrolytes (sodium, potassium, chloride, bicarbonate), osmolality, and fluid balance. Assess for signs of dehydration or hypervolemia. Fetal monitoring for heart rate abnormalities if used during labor.
Fertility EffectsNo data on effects on fertility. Osmotic diuretics may cause reversible electrolyte disturbances that could theoretically impair reproductive function, but no specific studies exist.

Warnings & precautions

■ FDA Black Box Warning

May cause osmotic nephrosis and acute renal failure, especially with doses >200 g or in patients with pre-existing renal disease.

Side Effect Profile

Serious Effects

Absolute Contraindications

Severe renal impairment (anuria)Pulmonary edemaActive intracranial bleedingHypersensitivity to mannitolSevere dehydration

Clinical Precautions

PrecautionsMonitor serum electrolytes, osmolarity, and renal function, Avoid extravasation as it may cause tissue necrosis, Use with caution in patients with cardiac or pulmonary congestion, May precipitate heart failure due to volume expansion
Food/DietaryNo specific food interactions. Maintain adequate hydration as directed. Patients with electrolyte imbalances may require dietary modifications (e.g., sodium or potassium adjustments) based on serum levels. Avoid excessive fluid intake unless instructed, as it may counteract the osmotic effect.

Clinical Tips & Counseling

Clinical PearlsOsmotrol 20% (mannitol) is a hyperosmotic agent used to reduce intracranial pressure (ICP) and cerebral edema. Administer via IV infusion using an in-line filter (pore size ≤5 microns) to prevent mannitol crystals from entering the circulation. Monitor serum osmolality closely; target <320 mOsm/L to avoid acute kidney injury. Rapid administration can cause transient hypervolemia, which may precipitate heart failure in susceptible patients. Onset of action typically within 15–30 minutes for ICP reduction. Extravasation risk: mannitol causes venous irritation; stop infusion immediately if pain or swelling occurs.
Patient AdviceThis medication is given through a vein to reduce swelling in the brain or to promote urine output. · Report any burning, pain, or redness at the IV site immediately. · You may experience increased thirst or a dry mouth during treatment. · Kidney function and blood levels will be monitored regularly while receiving this medication. · If you have a history of heart failure or kidney problems, inform your healthcare provider. · Do not drive or operate machinery if you feel dizzy or faint. · Tell your doctor about all other medications you are taking, especially diuretics or medications that affect kidney function.

OSMITROL 20% IN WATER IN PLASTIC CONTAINER Interactions

Loading safety data…

This overview is compiled from peer-reviewed clinical sources and FDA labeling. It's here to support — not replace — clinical judgment. Always verify dosing against your institution's current protocols before prescribing.

On this page

Mechanism of ActionDosing & administrationUse during pregnancyWarnings & precautionsDrug interactions

Compare with

ISMOTICMANNITOL 10%MANNITOL 10% IN PLASTIC CONTAINERMANNITOL 10% W/ DEXTROSE 5% IN DISTILLED WATERMANNITOL 15%

External sources

DailyMed (NIH) PubMed OpenFDA