Mannitol

Mannitol is an osmotic diuretic that is metabolically inert in humans and occurs naturally, as a sugar or sugar alcohol, in fruits and vegetables. Mannitol elevates blood plasma osmolality, resulting in enhanced flow of water from tissues, including the brain and cerebrospinal fluid, into interstitial fluid and plasma. As a result, cerebral edema, elevated intracranial pressure, and cerebrospinal fluid volume and pressure may be reduced. Mannitol may also be used for the promotion of diuresis before irreversible renal failure becomes established; the promotion of urinary excretion of toxic substances; as an Antiglaucoma agent; and as a renal function diagnostic aid.

Mannitol is a sugar alcohol used to test for asthma, to reduce intracranial and intraocular pressure, to measure glomerular filtration rate, and to manage pulmonary symptoms associated with cystic fibrosis.

Used for the promotion of diuresis before irreversible renal failure becomes established, the reduction of intracranial pressure, the treatment of cerebral edema, and the promotion of urinary excretion of toxic substances.

Mannitol is also indicated as add-on maintenance therapy for improving pulmonary function in cystic fibrosis patients aged 18 and over who have passed the BRONCHITOL tolerance test (BTT). It is recommended that patients take an orally inhaled short-acting bronchodilator 5-15 minutes prior to every inhaled mannitol dose.

• Acute Renal Failure (ARF)
• Cystic Fibrosis (CF)
• Edema of the cerebrum
• Increased Intra Ocular Pressure (IOP)
• Bladder irrigation therapy

Chemically, mannitol is an alcohol and a sugar, or a polyol; it is similar to xylitol or sorbitol. However, mannitol has a tendency to lose a hydrogen ion in aqueous solutions, which causes the solution to become acidic. For this reason, it is not uncommon to add a substance to adjust its pH, such as sodium bicarbonate. Mannitol is commonly used to increase urine production (diuretic). It is also used to treat or prevent medical conditions that are caused by an increase in body fluids/water (e.g., cerebral edema, glaucoma, kidney failure). Mannitol is frequently given along with other diuretics (e.g., furosemide, chlorothiazide) and/or IV fluid replacement.

Inhaled mannitol has the possibility to cause bronchospasm and hemoptysis; the occurrence of either should lead to discontinuation of inhaled mannitol.

Mannitol is an osmotic diuretic that is metabolically inert in humans and occurs naturally, as a sugar or sugar alcohol, in fruits and vegetables. Mannitol elevates blood plasma osmolality, resulting in enhanced flow of water from tissues, including the brain and cerebrospinal fluid, into interstitial fluid and plasma. As a result, cerebral edema, elevated intracranial pressure, and cerebrospinal fluid volume and pressure may be reduced. As a diurectic mannitol induces diuresis because it is not reabsorbed in the renal tubule, thereby increasing the osmolality of the glomerular filtrate, facilitating excretion of water, and inhibiting the renal tubular reabsorption of sodium, chloride, and other solutes. Mannitol promotes the urinary excretion of toxic materials and protects against nephrotoxicity by preventing the concentration of toxic substances in the tubular fluid. As an Antiglaucoma agent mannitol levates blood plasma osmolarity, resulting in enhanced flow of water from the eye into plasma and a consequent reduction in intraocular pressure. As a renal function diagnostic aid mannitol is freely filtered by the glomeruli with less than 10% tubular reabsorption. Therefore, its urinary excretion rate may serve as a measurement of glomerular filtration rate (GFR).

The exact mechanism of action of inhaled mannitol in the symptomatic maintenance treatment of cystic fibrosis remains unclear. It is hypothesized that mannitol produces an osmotic gradient across the airway epithelium that draws fluid into the extracellular space and alters the properties of the airway surface mucus layer, allowing easier mucociliary clearance.

Approximately 7% of ingested mannitol is absorbed during gastrointestinal perfusion in uremic patients.

Inhalation of 635 mg of mannitol powder yields a plasma C_max of 13.71 μg/mL in 1.5 hours (T_max) and a mean systemic AUC of 73.15 μg*h/mL.

Mannitol administered intravenously has a volume of distribution of 34.3 L.

Mannitol is primarily excreted unchanged in the urine. Following oral inhalation of 635 mg of mannitol in healthy volunteers, 55% of the total dose was recovered unchanged in the urine; following oral or intravenous administration of 500 mg, the corresponding values were 54 and 87%, respectively.

Mannitol has an elimination half-life of 4.7 hours following oral administration; the mean terminal elimination half-life is similar regardless of administration route (oral, inhalation, and intravenous.

Intravenous administration of mannitol yields a total clearance of 5.1 L/hr and renal clearance of 4.4 L/hr.

Mannitol overdose may result in bronchoconstriction and should be counteracted using a short-acting bronchodilator and other symptomatic and supportive care, as necessary.

No interactions found.

• 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 gm/kg or 60 gm/m² of body surface area administered over a period of 2 to 6 hrs.

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

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