MANNITOL 20% IN PLASTIC CONTAINER
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 compartments into extracellular fluid. In the kidneys, it is freely filtered at the glomerulus but minimally reabsorbed, increasing tubular fluid osmolality and reducing water reabsorption, thereby promoting diuresis. It also reduces cerebral edema by creating an osmotic gradient that draws water from brain tissue into plasma.
| Metabolism | Mannitol is minimally metabolized in the liver; the majority (approximately 80%) is excreted unchanged in the urine via glomerular filtration. A small fraction may be metabolized to glycogen or oxidized to carbon dioxide and water. |
| Excretion | Renal: >90% as unchanged drug. Biliary/fecal: negligible. |
| Half-life | Terminal elimination half-life: 0.25–1.7 hours in normal renal function; prolonged in renal impairment. |
| Protein binding | Negligible (<0.1%), not bound to plasma proteins. |
| Volume of Distribution | 0.5–0.6 L/kg; primarily extracellular fluid distribution. |
| Bioavailability | IV: 100% (bioavailability not applicable for other routes). |
| Onset of Action | IV: diuresis within 1–3 hours; reduction of intracranial pressure within 15–30 minutes. |
| Duration of Action | IV diuresis: 1–3 hours; reduction of intracranial pressure: 2–6 hours. |
Intravenous: 50-100 g (250-500 mL of 20% solution) over 30-60 minutes; may repeat every 6-8 hours as needed. For cerebral edema: 1-2 g/kg IV over 30-60 minutes.
| Dosage form | INJECTABLE |
| Renal impairment | Contraindicated if anuria or severe renal impairment (GFR < 15 mL/min). Use with caution if GFR 15-30 mL/min; monitor serum osmolality and urine output. |
| Liver impairment | No specific adjustment required; use with caution in hepatic impairment due to risk of fluid overload. |
| Pediatric use | Intravenous: 0.25-1 g/kg/dose (1.25-5 mL/kg of 20% solution) over 30-60 minutes; may repeat every 6-8 hours. Maximum single dose: 2 g/kg. |
| Geriatric use | Start at lower end of dosing range (e.g., 0.5 g/kg); monitor renal function and fluid/electrolyte balance closely due to age-related renal decline and increased risk of volume overload. |
| 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 | It is unknown if mannitol is excreted in human breast milk. The M/P ratio is not established. Due to its low systemic absorption when used intravenously, minimal excretion into breast milk is expected. However, caution is advised; use only if clearly needed and consider the developmental benefits of breastfeeding versus the mother's clinical need. |
| Teratogenic Risk |
■ FDA Black Box Warning
None
| Common Effects | edema |
| Serious Effects |
["Anuria due to severe renal disease","Severe pulmonary edema or congestive heart failure","Active intracranial bleeding (except during craniotomy)","Severe dehydration","Hypertonic saline or mannitol allergy","Acute tubular necrosis with anuria"]
| Precautions | ["Risk of volume overload and pulmonary edema in patients with cardiac or renal impairment","Electrolyte disturbances (hyponatremia, hyperkalemia, hypochloremia) with prolonged use","Acute kidney injury due to osmotic nephrosis, especially with high doses or pre-existing renal disease","Intracranial volume rebound (rebound cerebral edema) after discontinuation","Extravasation risk: may cause tissue necrosis if infiltrates","Crystallization issues: mannitol may crystallize at low temperatures; inspect solution before administration"] |
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| Mannitol is a pregnancy category C drug. Animal studies have shown no teratogenic effects; however, there are no adequate and well-controlled studies in pregnant women. Mannitol should be used during pregnancy only if clearly needed. In the first trimester, risk is theoretical; osmotic diuresis may cause electrolyte imbalances affecting fetal development. In the second and third trimesters, rapid fluid shifts may impact placental perfusion. Use only if potential benefit justifies potential risk to the fetus. |
| Fetal Monitoring | Monitor serum electrolytes (sodium, potassium, chloride, calcium, phosphorus), serum osmolality, fluid balance, and renal function. In pregnancy, assess for signs of fluid overload or dehydration. Fetal heart rate monitoring may be considered in late pregnancy due to potential placental hypoperfusion. Monitor for maternal pulmonary edema, especially in preeclampsia or compromised cardiovascular status. |
| Fertility Effects | No human data on fertility effects are available. Animal studies have not reported adverse effects on fertility. Mannitol is not known to impair reproductive function or fertility at therapeutic doses. |