Description and indication for use
Alprostadil is a synthetic prostaglandin
used to relax the ductus arteriosus in early post-natal life, where a patent
ductus is critical for survival, including Tetralogy of Fallot, pulmonary
atresia, pulmonary stenosis, tricuspid atresia and transposition of the great
arteries.
Alprostadil can preserve ductal patency if
administered before anatomical closure occurs.
Over time, the ductus arteriosus rapidly loses its responsiveness to alprostadil, and consequently it is most effective
when commenced within 96 hours of birth.
Therefore, it is used as palliative therapy until surgery can be
performed.
Alprostadil also causes
vasodilation of all arterioles and inhibition of platelet aggregation.
Dose
To open a closed ductus
arteriosus:
0.1 micrograms/kg/minute
(100 nanograms/kg/min). An effect is
usually seen within 30-60 minutes. Reduce the dose once an effect is seen or as
directed by a Consultant.1
Doses > 0.1
micrograms/kg/minute are rarely more effective and may cause serious adverse
effects.3
To maintain patency of ductus arteriosus:
0.01 to 0.02
micrograms/kg/minute (10-20 nanograms/kg/min).1,
2
For persistent pulmonary hypertension
of the newborn (PPHN):
0.01 to 0.05
micrograms/kg/minute (10-50 nanograms/kg/min).2
Note:
Doses of up to 100 nanograms/kg/min have
been used for PDA patency.
Doses between 50 and 100 nanograms/kg/min
should be weaned and maintained at 5-10 nanogram/kg/min after response is
achieved.
Maximum dose should be no greater than 100
nanograms/kg/min.
Reconstitution/Dilution
Ampoule = 500 microgram in 1 mL (Stored
in refrigerator).
Note: (1000 nanograms = 1 microgram).
Use only sodium chloride
0.9% or glucose 5% as infusion fluids.4
For maintenance infusion:
Withdraw required amount
of Alprostadil and make up to ordered
volume with infusion
fluid.
If dose ordered is not measurable at 500 micrograms/mL, a dilution
can be made.
For example: a 1 in 10 dilution: take 1 mL
of 500 micrograms/mL solution and add to 9 mL
of sodium chloride 0.9% = 50 micrograms/mL. Withdraw
required dose and make up infusion as ordered.
Usual order will
be as follows:
Drug | How to make up | Dose equivalent | Dose range |
Alprostadil | 60 microgram/kg in 50 mL Sodium chloride 0.9% | 1 mL/hr - 0.02 microgram/kg/min (20 nanograms/kg/min) | 0.01 - 0.05 micrograms/kg/min (10 - 50 nanograms/kg/min) (Duct opening dose 100 nanograms/kg/min) |
Ref: RWH: Continuous IV Infusion Chart
For opening a closed ductus arteriosus:
Prepare maintenance infusion as above and
give 2.5 mL over 30 minutes (5 mL/hr) to give 100 nanograms/kg/min (set
volume limit).
Prepare fresh infusion solutions every 24
hours. Discard any solution more than 24
hours old.
Route and method of administration
IV Infusion: Given as a continuous infusion via an infusion syringe
pump.
IV route is preferred, although infusions
via a UAC placed at the ductal opening have been
used.3
2 points of IV access preferred.
Side effects
Apnoea - usually occurs in neonates under 2
kg within the first hour of administration.3
Fever.
Cutaneous flushing - secondary to
vasodilatation.
Bradycardia, hypotension, oedema.
Seizures.
Decreased platelet aggregation,
thrombocytopenia.
Special precautions
Caution in patients with bleeding tendencies and seizure disorders.
Contraindications
On balance it is appropriate to use in sick
patients with suspected but undiagnosed congenital heart disease even if total
anomalous pulmonary venous return with obstruction has not been ruled out.
Incompatibilities
Decomposes rapidly in acidic solutions. As
a general rule administer on its own although in an emergency it can be run
with other fluids provided it is added close to the patient end of the infusion
line.
Nursing responsibilities
Monitor with cardiorespiratory monitor and
oxygen saturation monitor.
Monitor blood pressure, preferably with an
arterial line.
Monitor temperature.
Ensure resuscitation/intubation equipment
available.
Do not mix with any other medications or
infusions in same line.
Do Not Bolus Other Drugs via Prostaglandin
Infusion.
Observe IV site carefully.
Maintain patent IV at all times.
Change IV syringe every 24 hours. When changing syringe, ensure line is clamped
to prevent administering a bolus. Ensure line is unclamped after lines changed.
Check that rate ordered corresponds with
dose required (nanograms/kg/min).
References
1.
RWH Neonatal Pharmacopoeia, 2nd
ed. 2005.
2.
RCH Paediatric Pharmacopoeia,
13th ed. 2002.
3.
Prostin VR Product Information,
Pfizer Australia Pty Ltd, 13/09/2005.
4.
Lawrence Trissel, Handbook on
Injecable Drugs, 17th ed. 2013.