Description and indication for use
Dexamethasone is a synthetic adrenocorticoid
possessing basic glucocorticoid actions and effects, with minimal
mineralocorticoid activity. It has
pronounced anti-inflammatory activity and is used in the treatment of Chronic Lung
Disease and Bronchopulmonary Dysplasia (BPD) to facilitate weaning of
mechanical ventilation. It is thought to
produce its effect on BPD by increasing surfactant synthesis, reducing
pulmonary oedema and by stabilisation of cell and lysosomal membranes. It may also be used to treat Tracheal (Glottic)
Oedema before and after tracheal extubation. It is also used to treat Cerebral Oedema.
Dexamethasone has a rapid onset of action,
with a duration of action between 36 and 54 hours. It is metabolised in the liver and excreted
in the urine as unchanged drug and metabolites.
Small amounts may be excreted in bile.
Dose
Bronchopulmonary Dysplasia, Chronic Lung Disease
IV and Oral:
Regimen 1:
0.25 mg/kg 12 hourly for 72 hours, then
0.15 mg/kg 12 hourly for 72 hours,
thereafter.
Decrease dose by 10% of the current dose
every three days until a dose of 0.1 mg/kg/day is reached.
Then the drug is given on alternate days
for 1 week, then discontinued.
If the drug is initially ineffective,
discontinue after 5 days.
Regimen 2 (pulse therapy):
0.25 mg/kg/dose 12 hourly for 3 days, then
cease for 7 days, then recommence.
Continue in a 10 day cycle, providing the
baby is still requiring O2 supplementation and is less than
corrected age 36 weeks.
Shorter courses, with doses starting at up
to 0.5 mg/kg/day (in divided doses) may also be used with individually designed
tapering off periods and dosages.
The length of the course will generally
depend on response and the determined weaning schedule.
** Other dosage regimes may be used at the
consultant’s discretion.
Tracheal Oedema:
IV:
0.25 mg/kg/dose 6-12 hourly IV for 3 to 6
doses.
(Total dose should not exceed 1 mg/kg/day).
Reconstitution/Dilution
Ampoule = 8 mg in 2 mL.
IV:
Withdraw 0.25 mL of 4 mg/mL solution and
add to 0.75 mL of sodium chloride 0.9% in a second 1 mL syringe = 1 mg/mL.
Discard excess volume to obtain required
dose or withdraw dose using another syringe.
Route and method of administration
IV:
Give injection using 1 mg/mL solution over
1 minute.
Flush with Sodium chloride 0.9%.
Not for IM use.
Side effects
Immunosuppression, increasing risk of
sepsis, especially with prolonged use. May also mask symptoms of infection.
Hyperglycaemia.
Hypertension.
Osteoporosis (prolonged use).
Acute/rapid withdrawal after more than 7
days of use can cause acute adrenal insufficiency (fever, hypotension,
hypoglycaemia and shock).
Hypokalaemia, hyponatraemia, oedema,
glycosuria, hypercalciuria and hypocalcaemia.
Special precautions
CAUTION in hypertension.
Contraindications
Untreated systemic bacterial infections.
Systemic fungal infections.
Incompatibilities
Dexamethasone must not be mixed together
with the following drugs: Chlorpromazine, Diazepam, Vancomycin, Doxapram.
Drug interactions
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Phenobarbitone, Phenytoin, Rifampicin
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May increase the metabolism of dexamethasone.
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Frusemide, Chlorothiazide, Amphotericin B
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May have synergisitic potassium depleting
effect.
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Nursing responsibilities
Ensure that oral anti-fungal medication,
such as Daktarin gel or Nilstat, has been prescribed prophylactically for
infants receiving a course of Dexamethasone.
Ensure that any infection has been treated.
Observe for signs of infection.
Monitor blood pressure 8 hourly for first 3
days, then 12 hourly for the duration of treatment.
Monitor blood glucose 12 hourly for first 3
days, then PRN.