OSMITROL 15% IN WATER
Clinical safety rating: caution
Comprehensive clinical and safety monograph for OSMITROL 15% IN WATER (OSMITROL 15% IN WATER).
Osmotic diuretic; increases plasma osmolality, drawing water from extravascular to intravascular space, thereby reducing intracranial and intraocular pressure.
| Metabolism | Minimal hepatic metabolism; excreted unchanged by the kidneys. |
| Excretion | Primarily renal excretion as unchanged drug; >97% eliminated by glomerular filtration within 24 hours. Minimal biliary/fecal elimination (<3%). |
| Half-life | Terminal elimination half-life is approximately 0.25–1.5 hours in patients with normal renal function; prolonged to 24–36 hours in anuria or severe renal impairment. |
| Protein binding | Negligible (<5%) protein binding; does not bind significantly to albumin or other plasma proteins. |
| Volume of Distribution | Volume of distribution is approximately 0.4–0.6 L/kg, confined primarily to extracellular fluid; little intracellular penetration. |
| Bioavailability | Not applicable (NA) due to intravenous administration only; oral bioavailability is negligible (not absorbed). |
| Onset of Action | Intravenous: Diuresis begins within 1–3 minutes; reduction of intracranial pressure occurs within 15–30 minutes after infusion start. |
| Duration of Action | Duration of diuresis is 2–6 hours; reduction of intracranial pressure lasts 3–8 hours depending on dose and renal function. Hemodynamic effects may persist longer in renal impairment. |
IV infusion of 50-200 g over 30-60 minutes as a 15% solution; typical adult dose is 1.5-2 g/kg every 6-8 hours.
| Dosage form | INJECTABLE |
| Renal impairment | Contraindicated in anuria or severe renal impairment (eGFR < 10 mL/min); use with caution in mild to moderate impairment, monitor serum osmolarity and renal function. |
| Liver impairment | No specific adjustment for Child-Pugh class; monitor for volume overload and electrolyte disturbances in severe hepatic impairment. |
| Pediatric use | IV infusion of 0.25-2 g/kg as a 15-20% solution over 30-60 minutes; dosing based on weight and clinical response. |
| Geriatric use | Start at lower end of dosing range; monitor for fluid overload, electrolyte imbalances, and renal function due to age-related decreased reserve. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for OSMITROL 15% IN WATER (OSMITROL 15% IN WATER).
| Breastfeeding | It is unknown if mannitol is excreted in breast milk. In lactating women, breast-feeding is not recommended during IV infusion of high-dose mannitol due to possible infant exposure to high osmolar load. M/P ratio not available. |
| Teratogenic Risk | Osmitrol (mannitol) 15% in water is FDA pregnancy category C. Animal studies have not been conducted; no well-controlled human studies exist. Mannitol is a high-osmolar agent that can cause maternal osmotic diuresis and fluid/electrolyte disturbances, potentially affecting fetal homeostasis. Risk in first trimester is unknown; in second and third trimesters, use only if clearly needed due to potential for maternal pulmonary edema or heart failure. |
■ FDA Black Box Warning
None FDA-approved.
| Serious Effects |
["Anuria due to severe renal disease","Well-established anuria due to severe renal disease","Pulmonary congestion or edema","Active intracranial bleeding (except during craniotomy)","Severe dehydration","Hypersensitivity to mannitol"]
| Precautions | ["Renal toxicity with high doses or prolonged use","Congestive heart failure exacerbation due to volume expansion","Electrolyte disturbances (hyponatremia, hypokalemia)","Rapid infusion may cause hypotension and seizures","Use with caution in patients with anuria or pre-existing renal disease"] |
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| Fetal Monitoring | Monitor maternal serum electrolytes (sodium, potassium, chloride, bicarbonate), BUN, creatinine, and urine output before and during infusion. Monitor for signs of pulmonary edema or congestive heart failure (dyspnea, rales, weight gain). Fetal heart rate monitoring may be considered during administration in pregnant patients. |
| Fertility Effects | No studies on fertility effects in humans. In animal studies, mannitol at high doses may cause testicular degeneration, but relevance to human fertility is unknown. |