Mannitol

Question 1

Actions (Pharmacodynamics) for Mannitol

Answer 1

❑ Diuresis: Increases the osmotic pressure of the glomerular filtrate, inhibiting tubular reabsorption of water and electrolytes, thus promoting diuresis and urinary elimination of certain drugs.
❑ In the brain the presence of mannitol in the cerebral vasculature creates an osmotic force that draws edematous fluid out of the brain.

Question 2

Trade Name for Mannitol

Answer 2

Osmitrol

Question 3

Drug classification for Mannitol

Answer 3

Osmotic diuretic

Question 4

Indications for the use of Mannitol

Answer 4

To reduce intracranial pressure or cerebral edema associated with head injury trauma and stroke with GCS of < 8 and one or more of abnormal pupils or abnormal motor exam (i.e. posturing).

Question 5

Dosage for Mannitol

Answer 5

Adult/Pediatric: 0.5-1.0 g/kg IV infusion over 15 min.; May repeat 0.25-2.0 g/kg over 30 min. q 4 hours

Question 6

Contraindications to Mannitol use

Answer 6

❑ CHF, pulmonary edema
❑ Severe dehydration or electrolyte depletion
❑ anuria

Question 7

Precautions for Mannitol use

Answer 7

❑ Impaired renal or hepatic function

❑ Hypotension – support BP with volume resuscitation and/or vasopressor therapy

Question 8

Is there a risk of increasing ICP when giving Mannitol?

Answer 8

There is no risk of increasing ICP because mannitol cannot exit the capillary beds of the brain. Mannitol can leave the vascular system at all capillary beds (except the brain) which may lead to edema.

Question 9

What must always be used when administering Mannitol?

Answer 9

It must always be administered through a micron filter as it is prone to crystallization.

Question 10

What would happen if you administered Mannitol and the patient has inadequate urinary output?

Answer 10

This may result in circulatory overload producing pulmonary edema or CHF.

Question 11

What may be a worrying side effect of Mannitol administration?

Answer 11

Excessive dieresis may produce hyponatremia or hypokalemia