1. Danielle DelVillano, Pharm.D.
Pharmaceutical Calculations: Intravenous Infusions, Parenteral Admixtures, and Rate-of-Flow Calculations
Danielle DelVillano, Pharm.D.

2. Objectives
Perform calculations for the adult and pediatric intravenous infusions
Perform calculations for intravenous additives
Perform rate-of-flow calculations for intravenous fluids

3. Introduction Injections Parenteral administration
Intravenous, intramuscular, intradermal
Parenteral administration
Anything other than enteral route
Intravenous infusions
IVPB, IV push, large volume parenteral
Administration set
Certain number of drops per mL

4. Problem 1
How many grams of dextrose and sodium chloride are used to prepare a 250 mL bag of D51/2NS for intravenous infusion?
250 mL * 0.05 = 12.5 g dextrose
250 mL * = g sodium chloride

5. Problem 2
A physician orders enalaprilat (Vasotec IV) 2 mg IVP for a hypertensive patient. A pharmacist delivers several 1 mL injections, each containing 1.25 mg enalaprilat. How many mL of the injection should be administered?
1.25 mg = 2 mg
1 mL x mL
x = 1.6 mL

6. Problem 3
Calculate the daily infusion volume of D10W to be administered to a neonate weighing 3 lb 8 oz on the basis of 60 mL/kg/day.
3 lb 8 oz --> 3.5 lbs = 1.6 kg
2.2
60 mL/kg/day * 1.6 kg = 96 mL/day

7. Problem 4
An intravenous infusion is to contain 15 mEq of potassium ion and 20 mEq of sodium ion in 500 mL D5W. Using potassium chloride containing 6g/30 mL and 0.9% NS injection, how many milliliters of each should be used to supply the required ions?
KCl NaCl
1 mEq = 74.5 mg mEq = 58.5 mg
15 mEq x mg mEq x mg
x = 1118 mg x = 1170 mg
6g = g g = 1.17 g
30 mL x mL mL x mL
x = 5.6 mL x = 130 mL

8. Rate of Flow Equations Rate (drops/min) = Vol (mL) * dripset (drop/mL)
Time (min)
Infusion time = Vol (mL)
Rate (mL/min)

9. Problem 5
A medication order calls for 1000 mL of D5W to be administered over an 8 hour period. Using an IV administration set that delivers 10 drops/mL, how many drops per minute should be delivered to the patient?
Rate = 1000 mL * 10 drops/mL
(8 hr * 60 min/hr)
Rate = 20.8 or 21 drops/min

10. Problem 6
An intravenous infusion contains 10 mL of a 1:5000 solution of isoproterenol hydrochloride and 500 mL of a 5% dextrose injection. At what flow rate should the infusion be administered to provide 5 mcg of isoproterenol hydrochloride per minute, and what time interval will be necessary for the administration of the entire infusion?

11. Problem 6
1g = x g 5000 mL 10 mL x = .002 g = 2 mg 2000 mcg = 5 mcg 510 mL x mL x = 1.28 mL per minute 1.28 mL = 510 mL 1 min x min x = 398 minutes, or ~6.5 hours

12. Questions

13. Reference
Ansel, H. C. (2009) Phamaceutical Calculations (13th Ed.). Philadelphia:Lippincott Williams & Wilkins, and Wolters Kluwer Publishers

14. Additional Problems

15. Chapter 13 Page 219
A physician prescribes amiodarone HCl IV (Cordarone) for a patient with ventricular fibrillation. The prescribing information is
Loading infusion
Rapid infusion over first 10 min mg/min
Slow infusion over the next 6 hours 1 mg/min
Maintenance infusion
Slow infusion over the remaining 18 hours 0.5 mg/min
Amiodarone HCl IV is available in 3 mL ampuls containing 50 mg/mL. The pharmacist uses a 100 mL bag of D5W for the rapid infusion and 250 mL bottles of D5W for the slow infusion.

16. Chapter 13 Page 219
How many milliliters from an amiodarone HCl IV ampul should be placed in the 100 mL bag for the rapid infusion?
What is the drug concentration in the rapid infusion, in mg/mL?
3 mL
1.46 mg/mL

17. Chapter 13 Page 219
If the pharmacist added the contents of 3 ampuls to each 250 mL bottle of D5W needed for the slow infusions, calculate the drug concentration in mg/mL
What rate of administration, in mL/hr, should the pharmacist have recommended during the 6 hour infusion segment?
c) 1.74 mg/mL
d) 34.5 mL/hr

18. Chapter 13 Page 219
Calculate the rate of administration in the last question in drops/minute with an administration set that delivers 15 drops/mL
Calculate the milligrams of drug administered by slow infusion over the 6 hour segment
e) 9 drops/min
f) 360 mg

19. Chapter 13 Page 219
Make the same calculation as in the last question but over the 18 hour segment
g) 540 mg

20. Chapter 13 Problem 3
A patient received 250 mL of an infusion at a rate of 40 mL/hr. What was the total infusion time in hours and minutes?
6 hours 15 minutes

21. Chapter 13 Problem 9
An emergency syringe contains lidocaine, 1 g/5 mL. How many milliliters should be used in preparing 250 mL of an infusion to contain 4 mg/mL of lidocaine in D5W?
5 mL

22. Chapter 13 Problem 13
A pharmacist receives a medication order for 300,000 units of penicillin G potassium to be added to 500 mL of D5W. The directions on the 1,000,000-unit vial state that if 1.6 mL of solvent are added, the solution will measure 2 mL. How many milliliters of the solution must be withdrawn and added to the D5W?
0.6 mL

23. Chapter 13 Problem 21
How many milliliters of an injection containing 1 g of drug in 4 mL should be used in filling a medication order requiring 275 mg of the drug to be added to 500 mL of D5W solution? If the solution is administered at the rate of 1.6 mL per minute, how many milligrams of the drug will the patient receive in 1 hour?
1.1 mL
52.8 mg

24. Chapter 13 Problem 31
If a physician orders 5 units of insulin to be added to a 1-liter intravenous solution of D5W to be administered over 8 hours, (a) how many drops per minute should be administered using an IV set that delivers 15 drops/mL, and (b) how many units of insulin would be administered in each 30-minute period?
31.25 drops/min
.3 units

25. Chapter 13 Problem 48
CARDENE IV (nicardipine hydrochloride) is administered in the short-term treatment of hypertension by slow intravenous infusion at a concentration of 0.1 mg/mL. A 10-mL ampule containing 25 mg of nicardipine hydrochloride should be added to what volume of D5W to achieve the desired concentration of infusion?
(a) 80 mL
(b) 100 mL
(c) 240 mL
(d) 250 mL
c) 240