MANNITOL 15%

Clinical safety rating: safe

Other diuretics may have additive effects Can cause fluid and electrolyte imbalances and pulmonary congestion.

How it works

Increases plasma osmolality, drawing water from intracellular and interstitial spaces into the vascular compartment, thereby reducing intracranial pressure and intraocular pressure. Acts as an osmotic diuretic in the kidneys, increasing urine flow by inhibiting water reabsorption in the proximal tubule and loop of Henle.

What the body does with it

Metabolism	Mannitol is not significantly metabolized; it is primarily excreted unchanged by the kidneys via glomerular filtration.
Excretion	Primarily renal (90-100% as unchanged drug); negligible biliary/fecal elimination.
Half-life	Terminal elimination half-life approximately 0.25-1.5 hours in normal renal function; prolonged to 24-36 hours in renal impairment.
Protein binding	Approximately 0-10% bound to plasma proteins (negligible binding).
Volume of Distribution	0.5-0.8 L/kg; primarily distributes in extracellular fluid (interstitial space).
Bioavailability	Intravenous: 100% (only route used therapeutically); not administered orally due to minimal absorption (oral bioavailability < 5%).
Onset of Action	Intravenous: osmotic diuresis begins within 1-3 minutes; peak effect in 30-60 minutes. Intracranial pressure reduction occurs within 15-30 minutes.
Duration of Action	Diuretic effect lasts 1-3 hours after IV infusion; intracranial pressure reduction persists for 2-6 hours depending on dose and renal function.

Classification & Brands

Dosing & administration

1-2 g/kg as a 15% solution intravenously over 30-60 minutes. Typical adult dose: 100-200 g (667-1333 mL of 15% solution) administered as a single dose for reduction of intracranial pressure or promotion of diuresis.

Dosage form	INJECTABLE
Renal impairment	Contraindicated in anuria due to severe renal disease. For GFR <50 mL/min, use with caution and monitor serum osmolarity and renal function. No specific dose reduction defined; consider alternative therapy if GFR <20 mL/min.
Liver impairment	No specific adjustment for Child-Pugh class. Use with caution in ascites or severe hepatic impairment due to risk of volume overload and electrolyte disturbances.
Pediatric use	0.25-1 g/kg (1.67-6.67 mL/kg of 15% solution) intravenously over 30-60 minutes. Repeat doses as needed based on clinical response, up to 1-2 g/kg.
Geriatric use	Initiate with lower doses (e.g., 0.5 g/kg) and titrate carefully due to increased risk of volume overload, electrolyte imbalance, and renal impairment. Monitor renal function, serum osmolarity, and fluid status closely.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Other diuretics may have additive effects Can cause fluid and electrolyte imbalances and pulmonary congestion.

FDA category	Animal
Breastfeeding	Mannitol is not known to be excreted into human milk. M/P ratio is not established due to lack of data. Due to its high molecular weight and poor oral bioavailability, infant exposure via breastfeeding is likely negligible. Use with caution in lactating women only if clearly needed.
Teratogenic Risk	Mannitol is a category C drug. First trimester: No well-controlled studies, but animal studies have not shown teratogenic effects; risk cannot be excluded. Second and third trimesters: Use only if clearly needed, as osmotic diuresis may cause fetal dehydration, electrolyte imbalances, or altered placental blood flow. There is no evidence of direct teratogenicity.

Warnings & precautions

■ FDA Black Box Warning

None

Side Effect Profile

Common Effects	edema
Serious Effects

Absolute Contraindications

Anuria due to severe renal disease, severe pulmonary congestion or edema, active intracranial bleeding (except during craniotomy), severe dehydration, and known hypersensitivity to mannitol.

Clinical Precautions

Precautions

May cause volume expansion, pulmonary congestion, or heart failure in patients with cardiac dysfunction. Monitor serum electrolytes, osmolality, and renal function. Use with caution in patients with renal impairment, as accumulation can cause metabolic acidosis. Risk of osmotic nephrosis or acute kidney injury with high doses or prolonged use. May exacerbate intracranial hemorrhage due to increased cerebral blood volume.

Clinical Tips & Counseling

Drug interactions

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MANNITOL 15%

Clinical safety rating: safe

Other diuretics may have additive effects Can cause fluid and electrolyte imbalances and pulmonary congestion.

How it works

What the body does with it

Metabolism	Mannitol is not significantly metabolized; it is primarily excreted unchanged by the kidneys via glomerular filtration.
Excretion	Primarily renal (90-100% as unchanged drug); negligible biliary/fecal elimination.
Half-life	Terminal elimination half-life approximately 0.25-1.5 hours in normal renal function; prolonged to 24-36 hours in renal impairment.
Protein binding	Approximately 0-10% bound to plasma proteins (negligible binding).
Volume of Distribution	0.5-0.8 L/kg; primarily distributes in extracellular fluid (interstitial space).
Bioavailability	Intravenous: 100% (only route used therapeutically); not administered orally due to minimal absorption (oral bioavailability < 5%).
Onset of Action	Intravenous: osmotic diuresis begins within 1-3 minutes; peak effect in 30-60 minutes. Intracranial pressure reduction occurs within 15-30 minutes.
Duration of Action	Diuretic effect lasts 1-3 hours after IV infusion; intracranial pressure reduction persists for 2-6 hours depending on dose and renal function.

Classification & Brands

Dosing & administration

Dosage form	INJECTABLE
Renal impairment	Contraindicated in anuria due to severe renal disease. For GFR <50 mL/min, use with caution and monitor serum osmolarity and renal function. No specific dose reduction defined; consider alternative therapy if GFR <20 mL/min.
Liver impairment	No specific adjustment for Child-Pugh class. Use with caution in ascites or severe hepatic impairment due to risk of volume overload and electrolyte disturbances.
Pediatric use	0.25-1 g/kg (1.67-6.67 mL/kg of 15% solution) intravenously over 30-60 minutes. Repeat doses as needed based on clinical response, up to 1-2 g/kg.
Geriatric use	Initiate with lower doses (e.g., 0.5 g/kg) and titrate carefully due to increased risk of volume overload, electrolyte imbalance, and renal impairment. Monitor renal function, serum osmolarity, and fluid status closely.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Other diuretics may have additive effects Can cause fluid and electrolyte imbalances and pulmonary congestion.

FDA category	Animal
Breastfeeding	Mannitol is not known to be excreted into human milk. M/P ratio is not established due to lack of data. Due to its high molecular weight and poor oral bioavailability, infant exposure via breastfeeding is likely negligible. Use with caution in lactating women only if clearly needed.
Teratogenic Risk	Mannitol is a category C drug. First trimester: No well-controlled studies, but animal studies have not shown teratogenic effects; risk cannot be excluded. Second and third trimesters: Use only if clearly needed, as osmotic diuresis may cause fetal dehydration, electrolyte imbalances, or altered placental blood flow. There is no evidence of direct teratogenicity.

Warnings & precautions

■ FDA Black Box Warning

None

Side Effect Profile

Common Effects	edema
Serious Effects

Absolute Contraindications

Anuria due to severe renal disease, severe pulmonary congestion or edema, active intracranial bleeding (except during craniotomy), severe dehydration, and known hypersensitivity to mannitol.