doc. Mannitol as electrolyte and diuretic agent

1. MANNITOL
By: Ala’a F. Hassan [Al-mahmoudia general hosp.]
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Its non electrolyteobligatory diureticsthat’smetabolically inertin human.
Indications
1. Promotion of dieresis, prevention & treatment of oliguric phaseof acute
renal failurealso as renal diagnostic aid.
2. Reduction of elevated intraocular pressure, intracranial pressureaswell
as cerebral edema.
3. Promotion of toxic substance’s urinary excretion
4. In children, recent studiesconsidered mannitol to be used ad therapeutic
measure in cystic fibrosisas well as mannitol challenge-asthma test.
Pharmacokinetics
 Availability:asirrigant sol. 5% w/v, as well as sol. For injection (25, 20, 15,
10 & 5% w/v).
 Compatibility:it’sincompatiblewith blood transfusion [unlessadd 20 mEq
NaCl to each L of mannitol]as well as additives[risk of precipitation]&
drugs as [cefepime, Imipenem, meropenem, diazepam, phenytoin &
liposomal doxorubicin].
 Crystallization occursover exposureto lowtemperaturewith greater
tendency mentioned with 20% w/v sol. Mostly.
 Absorption:only 7% of ingested mannitol during GIT profusion.
 Half life 45-100 min. whileonset of action rangesfrom min. (15-13 in ICP
reduction) to hrs(1-3 in diuresis).
 Pregnancy category B, used with caution in nursing mother.
 Safety, in pediatricsbelow12 yr is not yet established whilegeriatric
usage depends on weight, clinical &biological condition of pt. +
concomitant therapy used.

2. Dosage
 Geriatrics:50-200g/24hr period
 Adults:
--Test dose for marked oliguria/renal function test 0.2g/kg I.V. --infusion
over 3-5 min. (75ml of 20% sol.)
--ARF prevention during surgeries50-100g I.V. infusion
--Decreasing ICP & brain mass 1.5g/kg I.V. infusion over 30-60 min.
--IOP reduction 1.2-2g/kg I.V. infusion over 30-60 min. [preoperativeuse
adm. 60-90 min. beforesurgery]
 Pediatricssp. Guidelines
+WHO formulary for children 2008
Cerebral edema 1-12 mnth age 0.25-1.5g/kg
Renal function assessment 200mg/kg
+BNFC 2009
Neonatal edema 0.5-1g/kg
Oedema with 1mnth-18yr age1-5g/kg
Peripheral edema & ascitis1mnth-18yr 1-2g/kg
Contraindications
1. Hypersensitivity to mannitol
2. Pre-existing plasma osmolarity
3. Sever heart failure
4. Disturbanceof BBB
5. Well established anuria
6. Non responsiveness to test dose
7. Sever pulmonary congestion or edema
8. Sever intravascular volumedepletion
9. Sever dehydration &electrolyteimbalance
10.Progressiverenal/heart failureafter mannitol therapy

3. Adverseeffect & precautions
 Its hypertonic sol. - best administered via largeperipheral/central vein.
 Hypersensitivity reaction with fatal outcomesmay occur.
 Renal complicationsreported-recommend test doses to be done as well as
monitoring.
 CNS toxicity occurs-[notrecommended with traumatic brain injury, acute
stroke specifically].
 Hyperosmolarity, hypovolemia &electrolyteimbalancereported-
commend monitoring &[contraindicated with shock, renal dysfunction &
CHF].
 Associated neurologic A.Eoccurs.
 Circulatory A.E&blood disturbanceoccurs.
 GIT & metabolic disorder occurs.
 Administration A.Ealso reported
Interactions
1. With lab. Tests; falsely low result for inorganic phosphorous
Falsely +ve result with blood ethyleneglycol test
2. With drugs; potentiateeffect of other diuretics& NM-blocking agents
Inhibit lithium&methotrexateeffect
Increase risk of cumulativenephrotoxicity with cyclosporins
Increase ototoxic effect of aminoglycosides
Risk of hypokalemia-increasedigoxin toxicity
Decrease anticoagulantseffect.