OSMITROL 5% IN WATER IN PLASTIC CONTAINER
Clinical safety rating
cautionComprehensive clinical and safety monograph for OSMITROL 5% IN WATER IN PLASTIC CONTAINER (OSMITROL 5% IN WATER IN PLASTIC CONTAINER).
Osmotic diuretic that increases plasma osmolality, drawing water from intracellular spaces into extracellular fluid and increasing renal blood flow. It is filtered by glomerulus and not reabsorbed, leading to increased urinary output and reduction of intracranial/intraocular pressure.
| Metabolism | Primarily excreted unchanged by the kidneys (glomerular filtration). Minimal hepatic metabolism. |
| Excretion | Mannitol is excreted primarily by the kidneys via glomerular filtration, with approximately 80% of an administered dose appearing unchanged in urine within 3 hours. Less than 10% undergoes tubular reabsorption; negligible biliary or fecal elimination (<1%). |
| Half-life | The terminal elimination half-life is approximately 1.5 to 2 hours in adults with normal renal function. This can be prolonged to 6-12 hours in patients with renal impairment, requiring dose adjustment. |
| Protein binding | Essentially negligible; protein binding is less than 1% and not bound to any specific plasma proteins. |
| Volume of Distribution | Volume of distribution is approximately 0.5 L/kg, indicating distribution primarily in extracellular fluid. Mannitol does not readily cross cell membranes, so its distribution is limited to the extracellular space. |
| Bioavailability | Bioavailability is 100% after intravenous administration, as it is the only route of clinical use. Oral administration has negligible absorption (<1%) and is used only for bowel preparation, but no systemic bioavailability is expected. |
| Onset of Action | Onset of diuresis occurs within 1-3 minutes after intravenous administration, with peak diuresis at 30-60 minutes. Reduction in intracranial pressure begins within 15 minutes and peaks at 30-60 minutes. |
| Duration of Action | Duration of diuretic effect is 2-4 hours. For reduction of intracranial pressure, the effect lasts 2-6 hours, depending on dose and renal function. Prolonged use may lead to rebound intracranial hypertension. |
| Molecular Weight | 182.17 |
Intravenous infusion. Usual adult dose: 50-100 grams (500-1000 mL of 5% solution) administered over 30-60 minutes. Frequency: every 6-12 hours as needed for cerebral edema or reduction of intraocular pressure.
| Dosage form | INJECTABLE |
| Renal impairment | Contraindicated in anuria. For GFR <10 mL/min: avoid use. GFR 10-50 mL/min: reduce dose by 50% and monitor serum osmolarity. GFR >50 mL/min: no adjustment. |
| Liver impairment | No specific adjustment for Child-Pugh class. Use with caution in severe hepatic impairment due to risk of fluid overload. |
| Pediatric use | Intravenous infusion. Initial dose: 0.25-1 g/kg given over 30-60 minutes. May repeat every 8-12 hours. Maximum total daily dose: 2 g/kg. |
| Geriatric use | Start at lower end of dosing range (50 g) due to age-related renal decline. Monitor for hypovolemia, electrolyte disturbances, and pulmonary edema. Avoid use in patients with heart failure. |
| 1st trimester | Use only if clearly needed. Mannitol is a diuretic and may cause maternal volume depletion and electrolyte imbalances. Limited human data; animal studies show no evidence of teratogenicity but potential for adverse effects due to altered maternal physiology. |
| 2nd trimester | Use with caution. Monitor maternal fluid balance and electrolytes. May cause fetal dehydration or electrolyte disturbances. No known teratogenic effects. |
| 3rd trimester | Use with caution. Risk of fetal dehydration, electrolyte imbalances, and possible oligohydramnios. Monitor closely. Avoid near term due to potential for maternal volume contraction affecting placental perfusion. |
Clinical note
Comprehensive clinical and safety monograph for OSMITROL 5% IN WATER IN PLASTIC CONTAINER (OSMITROL 5% IN WATER IN PLASTIC CONTAINER).
| Placental transfer | Mannitol crosses the placenta. It is distributed in the fetal compartment and has been detected in fetal serum and amniotic fluid. The degree of transfer is significant enough to produce similar concentrations in fetal and maternal blood. |
| Breastfeeding | Mannitol is excreted into breast milk in low amounts. However, because of its low oral bioavailability, systemic absorption by the infant is unlikely. Use with caution in breastfeeding women, especially in high doses or prolonged therapy, due to potential for maternal dehydration and electrolyte disturbances. |
| Lactation Rating | L2 (Safer) |
| Teratogenic Risk | Osmitrol (mannitol) is classified as FDA Pregnancy Category C. Animal reproduction studies have not been conducted with mannitol. It is not known whether mannitol can cause fetal harm when administered to a pregnant woman. Mannitol crosses the placenta. Use during pregnancy only if clearly needed and potential benefits justify potential risks to the fetus. First trimester: Insufficient data to assess risk; theoretical risk of osmotic effects. Second and third trimesters: May cause fetal dehydration and electrolyte imbalances. High doses may induce uterine contractions. |
| Fetal Monitoring | Monitor maternal serum electrolytes (sodium, potassium, chloride), osmolality, fluid balance, and renal function. In pregnancy, monitor fetal heart rate and uterine activity during infusion due to risk of uterine contractions and fetal distress. Assess for signs of maternal volume overload or dehydration. Monitor urine output hourly. In preeclampsia monitoring: assess blood pressure and deep tendon reflexes. |
| Fertility Effects | No data on effects of mannitol on fertility. Osmotic diuretics are not known to impair fertility. Animal studies have not been conducted to evaluate fertility impairment. In vitro data suggest no direct reproductive toxicity. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
Anuria due to severe renal diseaseSevere pulmonary edema or congestionActive intracranial bleeding (except during craniotomy)Severe dehydrationHypersensitivity to mannitol or any component of the formulation
| Precautions | May cause electrolyte imbalances (hyponatremia, hypernatremia, hypokalemia), Risk of volume expansion and heart failure in patients with cardiac impairment, Monitor renal function and urine output; may precipitate acute renal failure in pre-renal azotemia, Intravenous use: administer via large vein to avoid phlebitis, Avoid extravasation (can cause tissue necrosis), Use with caution in patients with pulmonary congestion or severe dehydration |
| Food/Dietary | Avoid excessive salt intake as it may counteract the diuretic effect. No specific food restrictions, but maintain a balanced diet as tolerated. Monitor fluid intake as directed by healthcare provider. |
| Clinical Pearls | Osmitrol 5% (mannitol) is an osmotic diuretic used to reduce intracranial pressure and cerebral edema. Administer via IV infusion with an in-line filter to prevent crystallization. Monitor serum osmolality; stop infusion if osmolality exceeds 320 mOsm/L to avoid acute kidney injury. Use cautiously in patients with pulmonary edema or congestive heart failure due to fluid overload risk. May cause transient hypervolemia followed by diuresis. |
| Patient Advice | This medication is given intravenously to reduce brain swelling or pressure inside the eye. · You may experience increased thirst, headache, or frequent urination during treatment. · Report any chest pain, difficulty breathing, or swelling in your legs immediately. · Drink fluids only as directed by your healthcare provider; do not consume extra water. · You may need blood tests to monitor your kidney function and electrolyte levels. |
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