MANNITOL 5% IN PLASTIC CONTAINER
Clinical safety rating
safeOther diuretics may have additive effects Can cause fluid and electrolyte imbalances and pulmonary congestion.
Mannitol is an osmotic diuretic that increases the osmolarity of the glomerular filtrate, reducing tubular reabsorption of water and solutes. It also draws water from intracellular spaces into the extracellular fluid, reducing cerebral edema and intraocular pressure.
| Metabolism | Mannitol is not metabolized; it is excreted unchanged by the kidneys via glomerular filtration, with minimal tubular reabsorption. |
| Excretion | Renal: >90% as unchanged drug via glomerular filtration; negligible biliary or fecal elimination. |
| Half-life | Terminal elimination half-life: 1–2 hours (adults with normal renal function); prolonged to 24–48 hours in severe renal impairment. |
| Protein binding | Negligible (<0.5%); no specific binding proteins. |
| Volume of Distribution | 0.5–0.6 L/kg; distributes primarily in extracellular fluid, does not cross cell membranes except under specific conditions (e.g., disrupted blood-brain barrier). |
| Bioavailability | IV: 100%. Oral: negligible (<10%) due to poor absorption; not administered orally for systemic effects. |
| Onset of Action | IV: Diuresis within 1–3 hours, reduction of intracranial pressure within 15–60 minutes. |
| Duration of Action | IV diuresis: 6–8 hours; reduction of intracranial pressure: 3–6 hours. Note: Duration may be shorter in renal impairment. |
| Molecular Weight | 182.17 |
50-100 g intravenously over 30-60 minutes for initial dose in acute renal failure or cerebral edema; maintenance dose 25-50 g every 6-8 hours based on serum osmolality and urine output.
| Dosage form | INJECTABLE |
| Renal impairment | Avoid use in anuria; GFR < 20 mL/min: contraindicated; GFR 20-50 mL/min: use with caution, monitor serum osmolality and fluid balance, reduce dose by 50% and extend interval to every 12-24 hours. |
| Liver impairment | No specific dose adjustment for hepatic impairment; caution in ascites due to potential volume overload. |
| Pediatric use | 0.25-2 g/kg intravenously over 30-60 minutes, not to exceed 60 g in total dose; dose based on clinical indication and serum osmolality. |
| Geriatric use | Start at lower end of dosing range (25-50 g), monitor renal function and serum osmolality; increased risk of volume overload and electrolyte disturbances; avoid if pre-existing renal impairment. |
| 1st trimester | Mannitol is FDA pregnancy category C. Use only if clearly needed. No well-controlled studies in first trimester. Potential for electrolyte imbalance and osmotic effects. Consider risk-benefit. |
| 2nd trimester | Limited data; use with caution. Monitor maternal fluid and electrolyte status. May cause fetal dehydration or electrolyte disturbances. |
| 3rd trimester | Use with caution near term. May cause fetal dehydration or electrolyte imbalance. Avoid if signs of maternal volume overload. |
Clinical note
Other diuretics may have additive effects Can cause fluid and electrolyte imbalances and pulmonary congestion.
| FDA category | Animal |
| Placental transfer | Mannitol crosses the placenta, but the extent and rate are not well defined. It is a small molecule (182.17 Da) and likely crosses by simple diffusion. |
| Breastfeeding | Mannitol is excreted into breast milk in small amounts. No known adverse effects in infants. However, due to potential for osmotic diuresis and electrolyte effects in the infant, use with caution, especially in dehydrated or ill infants. |
| Lactation Rating | L2 (Probably Compatible) |
| Teratogenic Risk | Mannitol is a pregnancy category C drug. In the first trimester, use is generally avoided due to lack of safety data; however, no teratogenic effects have been reported in animal studies at clinically relevant doses. In the second and third trimesters, administration may cause fetal dehydration, electrolyte imbalances, or osmotic shifts, particularly with high doses or prolonged infusion. Use only if clearly indicated (e.g., for cerebral edema in preeclampsia/eclampsia). Fetal monitoring for signs of fluid and electrolyte disturbance is recommended. |
| Fetal Monitoring | Monitor maternal serum electrolytes (sodium, potassium, chloride), osmolality, renal function (BUN, creatinine), and urine output. Assess for signs of fluid overload (e.g., pulmonary edema) or dehydration. Fetal monitoring includes heart rate tracing and assessment of amniotic fluid volume via ultrasound, as osmotic diuresis may reduce amniotic fluid. Observe for maternal hypotension or hypertension. |
| Fertility Effects | No adverse effects on fertility have been reported in human or animal studies with mannitol. However, as an osmotic diuretic, it could potentially affect ovarian function indirectly through electrolyte disturbances, but no specific data are available. Use in pregnant women for acute conditions has not been associated with long-term fertility impairment. |
■ FDA Black Box Warning
None.
| Common Effects | edema |
| Serious Effects |
Anuria due to severe renal diseaseSevere pulmonary congestion or edemaActive intracranial bleeding (except during craniotomy)Severe dehydrationKnown hypersensitivity to mannitol
| Precautions | Monitor renal function, serum electrolytes, fluid balance, and osmolality during therapy., Risk of volume overload, pulmonary edema, or heart failure in patients with impaired cardiac function., May cause electrolyte disturbances (e.g., hyponatremia, hyperkalemia) and dehydration., Use with caution in patients with severe renal impairment, anuria, or congestive heart failure., Hypersensitivity reactions may occur. |
| Food/Dietary | No specific food interactions. Maintain adequate fluid intake unless fluid restriction is prescribed (e.g., for hyponatremia or cerebral edema). Avoid excessive salt to prevent fluid retention. |
| Clinical Pearls | Mannitol 5% is an osmotic diuretic. Monitor serum electrolytes, osmolality, and renal function before and during infusion. Avoid extravasation due to risk of tissue damage. Use in patients with intracranial hypertension requires careful titration to maintain cerebral perfusion pressure. Contraindicated in anuria, pulmonary edema, or active intracranial bleeding. |
| Patient Advice | This medication increases urine output; stay hydrated unless advised otherwise. · Report difficulty urinating, chest pain, or shortness of breath immediately. · Avoid sudden position changes to prevent dizziness from fluid shifts. · Inform your doctor if you have kidney disease, heart failure, or are pregnant. |
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