AXATOL-20

Indications

• Cerebral edema
• Elevated intracranial pressure
• Acute kidney injury
• Oliguria
• Glaucoma
• Renal function diagnostic aid

Dosage

Adults: For cerebral edema, administer 0

Mechanism of action

Mannitol elevates blood plasma osmolality, resulting in enhanced flow of water from tissues, including the brain and cerebrospinal fluid, into interstitial fluid and plasma. This action reduces cerebral edema and intracranial pressure. As a diuretic, it increases the osmolality of glomerular filtrate, leading to increased urinary excretion of water and preventing sodium and chloride reabsorption in the renal tubules. Mannitol also facilitates the urinary excretion of toxic substances and can help in assessing renal function by measuring glomerular filtration rate (GFR).

Pharmacodynamics

Mannitol is classified as an osmotic diuretic. It is chemically similar to other sugar alcohols but has a unique ability to promote diuresis by remaining unabsorbed in the renal tubules. Its use is indicated for conditions associated with increased body fluids, such as cerebral edema and glaucoma. Mannitol may be combined with other diuretics to enhance diuretic efficacy. Inhaled formulations are used in cystic fibrosis, though they may cause bronchospasm and hemoptysis.

Pharmacokinetics

Mannitol is freely filtered by the glomeruli with less than 10% tubular reabsorption, which allows for its urinary excretion rate to serve as a measurement of GFR. It does not undergo significant metabolism and is eliminated primarily through the kidneys. The onset of action occurs within 30 to 60 minutes after intravenous administration, with effects lasting for several hours. Administration may require monitoring of renal function and fluid balance.

Contra-indications

• Anuria
• Severe dehydration
• Severe renal impairment
• Intracranial bleeding

Adverse effects

• Asthenia
• Gastrointestinal disturbances
• Dry mouth
• Confusion
• Visual impairment
• Hypotension
• Electrolyte imbalances
• Pulmonary edema
• Hemoptysis (with inhalation use)
• Bronchospasm (with inhalation use)

Interactions

• Potassium-sparing diuretics may increase the risk of hyperkalemia
• Other diuretics may have additive effects
• Caution with nephrotoxic agents

Precautions

• Caution in patients with diabetes mellitus
• Caution in the elderly
• Caution in patients with gout
• Caution in patients with hepatic impairment
• Monitor renal function and electrolytes regularly
• May cause blue fluorescence of urine

Pregnancy

Manufacturer advises avoid due to potential toxicity in animal studies.

Breast-feeding

Manufacturer advises avoid due to lack of information available.

Storage

Store in a cool, dry place, away from light. Do not freeze.

Formulations

• Solution for injection
• Inhalation powder
• Oral solution

Mechanism of action

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. MANNITOL IS.../USED/ IN PROPHYLAXIS OF ACUTE RENAL FAILURE. IT IS USED FOR THIS PURPOSE IN CONDITIONS AS DIVERSE AS CARDIOVASCULAR OPERATIONS, SEVERE TRAUMATIC INJURY, OPERATIONS IN THE PRESENCE OF SEVERE JAUNDICE, AND MGMNT OF HEMOLYTIC TRANSFUSION REACTIONS. IN EACH OF THESE CONDITIONS, A PRECIPITOUS FALL IN THE FLOW OF URINE MAY BE ANTICIPATED EITHER AS THE RESULT OF AN ACUTELY REDUCED FILTRATION RATE OR FROM ACUTE CHANGES IN TUBULAR PERMEABILITY. THE LATTER MAY BE CONSEQUENCE OF THE PRESENCE OF NOXIOUS AGENT WITHIN THE TUBULAR FLUID IN EXCESSIVELY HIGH CONCN, IN SOME INSTANCES SUFFICIENT TO RESULT IN ACTUAL PRECIPITATION. IN THESE SITUATIONS, MANNITOL EXERTS OSMOTIC EFFECT WITHIN THE TUBULAR FLUID, INHIBITS WATER REABSORPTION, & MAINTAINS THE RATE OF URINE FLOW. ...CONCN OF TOXIC AGENT WITHIN TUBULAR FLUID DOES NOT REACH EXCESSIVELY HIGH LEVELS THAT OTHERWISE WOULD HAVE BEEN ACHIEVED BY MORE COMPLETE REABSORPTION OF WATER. ...EVEN THOUGH /GLOMERULAR/ FILTRATION RATE IS REDUCED, MANNITOL IS STILL FILTERED @ GLOMERULUS. THE TUBULAR IMPERMEABILITY TO MANNITOL IS NOT ALTERED BY ACUTE RENAL ISCHEMIA OF SHORT DURATION. HENCE, THE MANNITOL THAT IS FILTERED IS ALSO EXCRETED IN THE VOIDED URINE. UNREABSORBED SOLUTE LIMITS BACK DIFFUSION OF WATER. ...URINE VOL CAN BE MAINTAINED EVEN IN PRESENCE OF DECR GLOMERULAR FILTRATION.

Pharmacodynamics

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.