MANNITOL 10% W/ DEXTROSE 5% IN DISTILLED WATER
Clinical safety rating: safe
Other diuretics may have additive effects Can cause fluid and electrolyte imbalances and pulmonary congestion.
Mannitol is an osmotic diuretic that increases plasma osmolality, drawing water from intracellular spaces into the extracellular fluid and bloodstream, thereby reducing cerebral edema and promoting diuresis. Dextrose provides a source of calories and may help prevent hypoglycemia.
| Metabolism | Mannitol is not significantly metabolized; it is excreted unchanged by the kidneys. Dextrose is metabolized via glycolysis to pyruvate and lactic acid, and enters the Krebs cycle for energy production. |
| Excretion | Primarily renal excretion: Mannitol is filtered by glomeruli and not reabsorbed, excreted unchanged in urine (approximately 80-90% within 24 hours). Biliary/fecal elimination is negligible (<5%). Dextrose is metabolized to CO2 and water; any excess is excreted renally as glucose if threshold exceeded. |
| Half-life | Terminal elimination half-life of mannitol is approximately 1.5-2 hours in patients with normal renal function. Clinically, duration of osmotic diuresis parallels half-life; in renal impairment, half-life may extend to 24-36 hours, increasing risk of fluid overload and electrolyte disturbances. |
| Protein binding | Mannitol is not significantly bound to plasma proteins (<1%). Dextrose is not protein bound. |
| Volume of Distribution | Approximately 0.5-0.6 L/kg. Mannitol distributes primarily in extracellular fluid (ECF); it does not enter cells significantly. Clinically, this low Vd indicates confinement to ECF, important for osmotic effects. |
| Bioavailability | Intravenous: 100% bioavailability. Oral bioavailability is negligible (<10%) as mannitol is poorly absorbed and acts as an osmotic laxative; Dextrose is well absorbed orally (100%) but not relevant for this IV formulation. |
| Onset of Action | Intravenous: Onset of diuresis occurs within 1-3 hours after infusion initiation; reduction of intracranial pressure (ICP) and intraocular pressure (IOP) begins within 15-30 minutes with peak effect at 30-60 minutes. |
| Duration of Action | Diuretic effect lasts approximately 3-6 hours following IV infusion. ICP/IOP reduction duration is 2-6 hours; repeated doses may be needed. Clinical monitoring of urine output, electrolytes, and osmolality is essential. |
Adult: 50-100 g (500-1000 mL of 10% solution) intravenously over 1-2 hours, repeated as needed every 6-12 hours. Individualize based on urine output and serum osmolality.
| Dosage form | INJECTABLE |
| Renal impairment | Contraindicated in anuria or severe renal impairment (GFR < 20 mL/min). For GFR 20-50 mL/min, use with caution and monitor serum osmolality; reduce dose or extend interval. No specific dose reduction formula established. |
| Liver impairment | No specific adjustments required for hepatic impairment. Monitor fluid and electrolyte balance due to potential volume expansion. |
| Pediatric use | 0.25-1 g/kg (2.5-10 mL/kg of 10% solution) intravenously over 30-60 minutes, repeated as needed. Max dose 2 g/kg/day. Adjust based on response and serum osmolality. |
| Geriatric use | Use lower initial doses and monitor renal function and electrolytes closely due to age-related decline in renal function and higher risk of volume overload. Start at 25-50 g (250-500 mL of 10% solution) and titrate. |
| 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 | Not known if mannitol or dextrose are excreted in breast milk. Consider risk of osmotic diarrhea in neonate if present in milk. M/P ratio not established. |
| Teratogenic Risk | No evidence of teratogenicity in animal studies; limited human data. Mannitol crosses the placenta; risk of fetal electrolyte disturbances and dehydration with maternal overdose. First trimester: theoretical risk only, no reported malformations. Second/third trimesters: monitor for maternal hyperosmolality and fluid shifts which may affect fetal hydration status. |
■ FDA Black Box Warning
None.
| Common Effects | edema |
| Serious Effects |
["Anuria due to severe renal disease","Severe dehydration","Intracranial hemorrhage (unless during craniotomy)","Active intracranial bleeding except during craniotomy","Hypersensitivity to mannitol or dextrose","Congestive heart failure","Pulmonary edema"]
| Precautions | ["Monitor serum electrolytes, osmolality, and renal function during therapy","May cause fluid and electrolyte imbalances, including hyponatremia or hypernatremia","Administer cautiously in patients with renal impairment, heart failure, or pulmonary edema","Use with caution in conditions where increased intravascular volume may be harmful","Do not administer if solution contains particulate matter or is discolored"] |
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| Fetal Monitoring | Maternal: serum electrolytes, osmolality, renal function, urine output; fetal: heart rate monitoring during infusion; avoid rapid infusion to prevent maternal fluid overload and fetal distress. |
| Fertility Effects | No known adverse effects on fertility in animal studies; no human data on reproductive function. |