Medication Calculations

Question 1

Standard Formula for Medication Dosage

Answer 1

Desired (dose prescribed) divided by Available (dose available) X Quantity

Question 2

There’s an order for 18,000 mcg of Ampicillin. Ampicillin is available as 0.012 kg per tablet. What should the nurse administer?

Answer 2

1) Convert: 0.012kg = 12,000,000 mcg
2) Formula: 18,000mcg/12,000,000 mcg x 1 tab
3) Answer: 1.5 tablets

Question 3

Flow Rate Formula

Answer 3

Total volume x drop factor/ time in mins = drops per minute

Question 4

Calculate the IV Flow rate for 0.61L of 0.9% NaCl IV over 21.5 hr. Infusion set has drop factor of 62 gtts/ml. What is the IV flow rate in gtts/min?

Answer 4

1) Convert: 0.61L to 610 ml and 21.5 hours to 1290 minutes
2) 610 ml X 62 = 37,820 gtts
3) 37,820 gtts/ 1290 minutes
4) Final Answer: 29 gtts/minute

Question 5

mL per hour Formula

Answer 5

total V in mL/ number of hours = mL per hour

Question 6

Ordered 49 mL NS IV to infuse in 12.5 hr by infuision pump. What is the IV flow rate in mL/hr?

Answer 6

3.92 mL/hr

Question 7

Infusion Time Formula

Answer 7

total volume to infuse/ mL per hour being infused = infusion time