A patient weighing 60 kilograms is ordered an Alprostadil infusion at
a dose of 50 milligram per kilo per minute. If the infusion solution
is 500 micrograms in 50 mls what is the hourly rate of the infusion?

---

Request for Question Clarification by livioflores-ga on 01 Sep 2003 07:38 PDT

Hi aquarius, I did the problem, but the result is something extrange
(about 300 liters per minute!!), are you sure that the dose is 50
milligram and the infusion solution is 500mcg in 50ml (may be the
units are wrong)?
Thank you.

Since this question has been answered by boquinha-ga and
livioflores-ga, who both got the same (impossible) answer (patient
would explode at 300 l/min), I thought we should look at the numbers
associated with the drug Alprostadil.
http://answers.google.com/answers/main?cmd=threadview&id=250872

At 60 kilograms (132 pounds), the patient probably isn't a newborn,
but the info for those applications are also listed for comparison.

Based on the following websites, you probably want a dose of 50
nanograms per kilo per minute, one-millionth of the rate using
milligrams.  To get in units of mcg:
50 ng/kg/min * (1 mcg/1000 ng) = 0.05 mcg/kg/min.

Using the new dose (and the others' calculation), you would get 0.3
ml/min

http://www.nursespdr.com/members/database/ndrhtml/alprostadil.html
"Dosage
•Continuous IV Infusion or Umbilical Artery Maintain patency of ductus
arteriosus.
Initial: 0.05-0.1 mcg/kg/min; then, after response achieved, decrease
infusion rate to lowest dose that will maintain response (e.g.,
0.1-0.05 to 0.025-0.01 mcg/kg/min). NOTE: If 0.1 mcg/kg/min is
insufficient, dosage can be increased up to 0.4 mcg/kg/min."

Alprostadil (PGE1) in Liver Transplantation
http://www.home.eznet.net/~webtent/alprostadil.html
http://www.home.eznet.net/~webtent/alprostadil_protocol.html
"Alprostadil (PGE1) is prepared as 500 µg/100mL of D5W (final
concentration = 5 µg/mL)."
"we normally aim for final rate 0.6 µg/kg/hr."
(0.6 µg/kg/hr * (1hr/60min) = 0.01 µg/kg/min)
"maximum rate of 1 µg/kg/hr"

Calculator (for newborn)
http://www.adhb.govt.nz/newborn/DrugProtocols/Calculators/ProstaglandinCalculator.htm

Additional IV Problems
http://www.accd.edu/sac/nursing/math/ivprob.html
http://academic.cuesta.edu/nursing/math.htm

Labeling Changes by FDA for Alprostadil
http://www.fda.gov/medwatch/safety/2000/sep00.htm#edex
http://www.fda.gov/medwatch/safety/1999/jul99.htm#caverj
...