A hospital pharmacy receives a medication order for 500 mg aminophylline in 250
ID: 122105 • Letter: A
Question
A hospital pharmacy receives a medication order for 500 mg aminophylline in 250 mL normal saline solution for a 132-lb patient. The aminophylline is to be administered at a dose of 300 mu g/kg/h using an IV set that delivers 60 drops/mL. The pharmacy has 20-mL vials of injection containing aminophylline, 25 mg/mL. Calculate the following: (a) The milliliters of aminophylline injection that should be added to the normal saline solution. (b) The total volume of the intravenous infusion. (c) The milligrams of aminophylline administered per hour. (d) The duration, in hours, for the complete infusion. (e) The number of milliliters of infusion delivered per hour (flow rate, mL/h). (f) The number of drops administered per minute (flow rate, drops/min).Explanation / Answer
a. 25mg of Aminophylline is present in 1ml of injection.
As 500 mg of drug is to be administered, therefore, 500 mg Aminophylline will be present in:
500/25 = 20 ml of injection.
20 ml of injection should be added to the normal saline solution.
b. 250 ml of normal saline is taken and 20 ml injection added.
So, total volume of intravenous infusion = 250 + 20 = 270 ml
c. The dose of Aminophylline is 300 microgm/kg/hr, converting microgm into mg, i.e. 0.3 mg/kg/hr.
Weight of the patient is 132 lb = 59.87 kg.
0.3 mg aminophhyline is administered per kg in 1 hour, so, for 59.87 kg patient, amount of drug administerd per hour will be:
0.3 X 59.87 = 17.96 mg/hr.
d. 17.96 mg aminophylline is administered in 1 hour. So, 500 mg of aminophylline will be administered in:
500/ 17.96 = 27.83 hours
e. 17.96 mg aminophylline is administered in 1 hour.
270 ml of infusion contains 500 mg of aminophylline.
Therefore, 17.96 mg aminophylline will be present in:
(270 X 17.96) / 500 = 9.7 ml of infusion
9.7 ml of infusion will be delivered in 1 hour. Flow rate 9.7 ml/hr.
f. 60 drops/ml are administered
Flow rate is 9.7 ml/hr, therefore, number of drops per hour for 9.7 ml infusion will be:
60 X 9.7 = 582 drops/hr or 582 drops/60min
Therefore, drops per min: 582/60 = 9.7 drops/min.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.