Mannitol is principally used by IV infusion as an osmotic diuretic to preserve renal function in acute renal failure and to reduce raised intracranial and intraocular pressure. Mannitol is also used as an irrigating solution to prevent hemolysis and hemoglobin buildup during transurethral prostatic resection. It is useful in the management of acute drug poisoning where elimination occurs through the kidneys. Besides these, it is also used for symptomatic relief of edema, reperfusion injury, termination of pregnancy, and bowel preparation. Mannitol is indicated in:

• Renal insufficiency
• Reperfusion injury
• Raised intracranial pressure
• Bladder irrigation
• Raised intraocular pressure
• Bowel preparation
• Edematous status
• As a prophylactic in renal failure
• Management of poisoning
• Termination of pregnancy

Mannitol is a clear, nearly colorless, sterile solution of Mannitol. Each 100 ml contains 20 g of Mannitol BP. When administered parenterally, Mannitol increases the osmotic pressure of plasma, drawing water out of body tissues and causing osmotic diuresis. Mannitol is mainly used via IV infusion as an osmotic diuretic to preserve renal function in acute renal failure and to reduce elevated intracranial and intraocular pressure. It is also used as an irrigating solution to prevent hemolysis and hemoglobin buildup during transurethral prostatic resection. Mannitol is helpful in the management of acute drug poisoning, where elimination occurs through the kidneys. Additionally, it is used for symptomatic relief of edema, reperfusion injury, termination of pregnancy, and bowel preparation.

The adult dose of Mannitol ranges from 50 to 100 g by IV infusion. The rate of administration is usually adjusted to maintain a urine flow of at least 30 to 50 ml/hr. Total dosage, concentration, and the rate of administration depend on fluid requirement, urinary output, and the severity of the condition being treated.

Renal insufficiency-

• Adults: 50 to 100 g of Mannitol administered at a rate adjusted to maintain a urine flow of at least 30 to 50 ml/hr.
• Children: 2 g/kg or 60 g/m² of body surface area administered over a period of 2 to 6 hrs.

Cerebral edema, elevated intracranial pressure, elevated intraocular pressure, Glaucoma-

• Adults: 1.5 to 2 g/kg administered over a period of 30 to 60 minutes.
• Children: 1 to 2 g/kg body weight or 30 to 60 g/m² of body surface area administered over a period of 30 to 60 mins.

Adjunctive therapy for removal of toxic substances-

• Adults: 50 to 200 g of Mannitol administered at a rate adjusted to maintain a urine flow of at least 100 to 500 ml/hr.
• Children: 2 g/kg or 60 g/m² of body surface area.

For termination of pregnancy :50 g of Mannitol (250 ml of Mannitol) is instilled into the amniotic cavity, which induces abortion in a high proportion of pregnancies.

Mannitol intravenous infusion is contraindicated in patients with pulmonary edema or congestive heart failure. It is also contraindicated in cases of inadequate urine output, dehydration, acidosis, intracranial bleeding, and in patients with renal failure unless a test dose has shown a diuretic response.

The most common side effects of Mannitol intravenous infusion are fluid and electrolyte imbalances, including circulatory overload and acidosis at high doses. Other side effects include nausea, vomiting, thirst, headache, dizziness, fever, tachycardia, chest pain, hyponatremia, dehydration, blurred vision, urticaria, and hypertension or hypotension.

The safety of Mannitol intravenous infusion during pregnancy has not been established. No information is available regarding the excretion of Mannitol in breast milk, so it should be administered only after careful consideration of the risk-benefit ratio.

Careful monitoring of the rate of Mannitol administration is necessary to avoid fluid and electrolyte imbalance and circulatory overload. The infusion should be discontinued if the patient shows signs of progressive renal dysfunction, heart failure, or pulmonary congestion. Mannitol should not be administered with whole blood. Stop infusion immediately if rigor occurs. Do not use if the solution is cloudy, contains particles, or has expired.

Osmotic diuretics

Store Mannitol at 20° to 30°C. Exposure to lower temperatures may cause crystal formation, which can be dissolved by warming the bottle in hot water for about 30 minutes. Cool to body temperature before use. If all crystals do not dissolve, do not use the solution. Use the contents of open containers promptly and discard any unused portion.