Mannitol Intravenous for Adults

Who can administer

May be administered by registered competent doctor or nurse/midwife

Important information

Crystallisation may occur - see under 'storage requirements' for further information
See 'Monitoring requirements' below
Flush line with Glucose 5% as there is a risk of precipitation with Sodium chloride 0.9% ^{(ref 1)}
Administer via central line or large peripheral vein
Extravasation causes inflammation and thrombophlebitis

Available preparations

Mannitol 10% 500mL infusion (50g in 500mL)

Mannitol 15% 500mL infusion (75g in 500mL)

Mannitol 20% 500mL infusion (100g in 500mL) (this product may not be available- it has been discontinued by some manufacturers)

Reconstitution

Already in solution

Infusion fluids

Not required - product ready for infusion

Methods of intravenous administration

Slow intravenous injection (test dose for patients with marked oliguria or suspected inadequate renal function)

Test dose over 3 to 5 minutes

Intermittent intravenous infusion

See under 'dose' for details
Administer via a giving set that incorporates a 15 micron in-line filter ^{(ref 1)} - check packaging of administration set for details)- see photo
The rate of infusion is usually adjusted to maintain a urine flow of at least 30 to 50mL/hour
In emergency situations, the maximum infusion rate can be as high as 0.2g/kg over five minutes

Dose in adults

Volume in ml of Mannitol solution required
	Required dose	15g	25g	50g	75g	100g	150g
10% solution		150ml	250ml	500ml	750ml	1000ml	1500ml
15% solution		100ml	167ml	333ml	500ml	667ml	1000ml
20% solution		75ml	125ml	250ml	375ml	500ml	750ml

Reduction of intracranial pressure, cerebral volume and intraocular pressure

Usual dose: 1.5 to 2g/kg infused over 30 to 60 minutes (some references suggest a range of 0.25 to 2g/kg ^{(ref 2)})
Dose may be repeated once or twice after 4 to 8 hours ^{(ref 2)}
See table above for guidance on the different volumes of mannitol required (depending on concentration)
When used pre-operatively, the dose should be administered 60 to 90 minutes before surgery to obtain the maximum effect

Use in patients with oliguria or renal impairment

A test dose (to assess renal function) of about 0.2g per kg should be administered over three to five minutes - this should produce a diuresis of at least 30 to 50ml/hour during the next two to three hours
A second test dose may be given if there is inadequate response to the first test dose
See table above for guidance on the different volumes of mannitol required (depending on concentration)
If the second test dose does not produce an adequate urine output, then need to reassess management

Acute renal failure

The general dose range for adults is 50 to 200g mannitol in a 24 hour period, with a dosage limit of 50g mannitol on any one occasion
In most instances, adequate response will be achieved at a dosage of 50 to 100g mannitol per day
The rate of administration is usually adjusted to maintain a urine flow of at least 30 to 50mL/hour
See table above for guidance on the different volumes of mannitol required (depending on concentration)

Promotion of elimination of renally excreted toxic substances in poisoning

An initial loading dose of 25g may be given
Adjust dose to maintain urinary output of at least 100ml/hour and positive fluid balance of 1 to 2 litres
See table above for guidance on the different volumes of mannitol required (depending on concentration)

Renal impairment

Use with caution in severe renal impairment
If the second test dose does not produce adequate urine output, reassess options

Monitoring

Renal function, fluid balance, serum electrolytes, serum and urine osmolality
Monitor central venous pressure
Assess cardiac function before and during treatment

Storage

Store between 20 and 30⁰C ^{(ref 1)}
Do not refrigerate or freeze
Solutions may crystallise, especially if stored at low temperatures
The administration set should contain a 15 micron in-line filter - see under method of administration above

Crystals may be redissolved by warming before use as follows:

Re-dissolve any crystals by warming to 37⁰C (Baxter products), or 60⁰C (Fresenius Kabi products)^{(ref 1)}
Use of dry heat (eg warming cabinet) is recommended - solutions should not be heated in water due to risk of contamination
Shake vigorously occasionally ^{(ref 1)}
Microwave heating should not be used
The product should be allowed to cool to 37⁰C before infusion

References

SPC March 2019

1. Injectable medicines administration guide, Medusa Accessed online 7th July 2023

2. BNF- accessed online 7th July 2023

Therapeutic classification

Osmotic diuretic

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