MANNITOL 10%
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 urinary output by raising the osmolarity of glomerular filtrate, thereby reducing tubular reabsorption of water and solutes. It also reduces cerebral edema by creating an osmotic gradient across the blood-brain barrier, drawing water from brain tissue into plasma.
| Metabolism | Mannitol is not metabolized in the body. It is eliminated unchanged by the kidneys via glomerular filtration with minimal tubular reabsorption. |
| Excretion | Renal: 90% as unchanged drug; <10% metabolized in liver to fructose and glucose; fecal: negligible |
| Half-life | Terminal half-life: 1.1–1.6 hours; prolonged to 6–36 hours in renal impairment |
| Protein binding | Negligible (<2%); does not bind to plasma proteins |
| Volume of Distribution | 0.36–0.5 L/kg; distributes primarily in extracellular fluid, limited CNS penetration due to hydrophilic nature |
| Bioavailability | IV: 100%; oral: negligible (<10%) due to poor absorption and osmotic diarrhea |
| Onset of Action | IV: 15–30 minutes for diuresis; ICP reduction: within 15 minutes; oral: not clinically relevant for systemic effects |
| Duration of Action | IV diuresis: 1–2 hours; ICP reduction: 2–6 hours; rebound effect may occur after administration |
0.25-2 g/kg intravenously as a 10% solution over 30-60 minutes, typically 50-100 g every 6-8 hours.
| Dosage form | INJECTABLE |
| Renal impairment | Contraindicated in anuria or severe renal impairment (GFR < 20 mL/min). For GFR 20-50 mL/min, reduce dose by 50% and monitor serum osmolality. |
| Liver impairment | No specific Child-Pugh based adjustment required; use with caution in severe hepatic impairment due to risk of fluid overload. |
| Pediatric use | 0.25-1 g/kg intravenously as a 10% solution over 30-60 minutes, repeated every 6-8 hours as needed. |
| Geriatric use | Start at lower end of dosing range (0.25-0.5 g/kg) due to decreased renal function; monitor fluid and electrolyte balance closely. |
| 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 | Mannitol is excreted into breast milk in low concentrations (estimated M/P ratio <0.1) due to its high molecular weight and hydrophilicity. Oral bioavailability in infants is negligible, and no adverse effects have been reported. However, caution is advised if used repeatedly or in high doses, as theoretical risk of neonatal electrolyte imbalance exists. |
| Teratogenic Risk |
■ FDA Black Box Warning
None
| Common Effects | edema |
| Serious Effects |
["Anuria due to severe renal disease","Severe pulmonary edema or congestion","Active intracranial bleeding (except during craniotomy)","Severe dehydration","Hypersensitivity to mannitol"]
| Precautions | ["Use with caution in patients with congestive heart failure due to risk of pulmonary edema from fluid overload","Monitor serum electrolytes (especially sodium and potassium) and renal function during therapy","May cause acute kidney injury with excessive doses or pre-existing renal impairment","In patients with intracranial hemorrhage, avoid rapid reduction of intracranial pressure","May cause expansion of extracellular fluid volume leading to pulmonary edema in patients with compromised cardiac function"] |
Loading safety data…
| Mannitol is a pregnancy category C drug. First trimester: Limited human data; animal studies indicate potential for fetal harm at high doses due to osmotic effects, but risk with clinical use is low. Second trimester: Generally safe for short-term use when indicated (e.g., elevated intracranial pressure), but avoid prolonged exposure to prevent fetal dehydration or electrolyte imbalances. Third trimester: Use cautiously; osmotic diuresis may cause maternal hypovolemia, potentially reducing placental perfusion and leading to fetal distress. |
| Fetal Monitoring | Monitor maternal serum electrolytes (sodium, potassium, chloride), serum osmolality, urine output, and blood pressure throughout infusion. Assess fetal heart rate and uterine activity during infusion, especially in third trimester. In preterm labor cases, monitor for signs of maternal pulmonary edema. Consider fetal ultrasound if prolonged therapy is required. |
| Fertility Effects | Animal studies have not demonstrated significant effects on fertility. No human data on male or female fertility impairment. High doses causing systemic osmotic shifts may theoretically affect reproductive organ function, but clinical relevance is low. |