OSMITROL 5% IN WATER IN PLASTIC CONTAINER
Clinical safety rating: caution
Comprehensive 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. |
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 | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for OSMITROL 5% IN WATER IN PLASTIC CONTAINER (OSMITROL 5% IN WATER IN PLASTIC CONTAINER).
| Breastfeeding | Mannitol is not systemically absorbed after oral administration. There are no reports of mannitol in breast milk. However, due to potential for excretion and lack of data, caution is advised. M/P ratio is unknown. Intravenous mannitol may be excreted into breast milk in low amounts; theoretical risk of osmotic diarrhea in the infant. Consider the developmental and health benefits of breastfeeding along with the mother's clinical need for the drug. |
| 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. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["Anuria due to severe renal disease","Pulmonary congestion or edema","Active intracranial hemorrhage (unless in the setting of craniotomy)","Severe dehydration","Hypersensitivity to mannitol"]
| 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"] |
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| 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. |