Medical Dosage Calculations

Question 1

What is the formula to calculate flow rate (mL/hr)?

Answer 1

low rate (mL/hr)= (total volume ml) / (infusion time hr)

Question 2

How do you calculate infusion time (hr)?

Answer 2

infusion time (hr)

total volume (mL) /
flow rate (mL/hr)

Question 3

What is the formula for total volume (mL)?

Answer 3

total volume (mL)

flow rate (mL/hr)
×
infusion time (hr)

Question 4

If you administer 1 L (1,000 mL) over 4 hours, what is the flow rate?

Answer 4

flow rate= 4 hr / 1000 mL
​
=250 mL/hr

Question 5

What is the conversion factor from pounds (lb) to kilograms (kg)?

Answer 5

kg=
lb / 2.2

​

Question 6

How do you convert milliliters (mL) to liters (L)?

Answer 6

L = ml / 1000

Question 7

What is the conversion from milligrams (mg) to grams (g)?

Answer 7

g = mg / 1000

Question 8

How do you convert micrograms (mcg) to milligrams (mg)?

Answer 8

mg = mcg / 1000

Question 9

What are some common unacceptable abbreviations in prescriptions?

Answer 9

DC or D/C: Discontinue or discharge (write it out).
HS: Half-strength or at bedtime (write at bedtime).
QD: Every day or right eye (write every day).
QOD: Every other day or daily (write every other day).

Question 10

What does “U” or “IU” stand for, and why should it be avoided?

Answer 10

It means “unit” but can be mistaken for “0” or “10” (write units).

Question 11

What does “IV” mean?

Answer 11

Intravenous

Question 12

What is the significance of understanding medical math in healthcare?

Answer 12

It ensures accurate medication dosing, enhances patient safety, and helps identify potential errors.

Question 13

What is the formula for converting fluid volumes from mL to L?

Answer 13

mL=L×1000

Question 14

How do you calculate the total volume if the flow rate is 200 mL/hr and the infusion time is 3 hours?

Answer 14

total volume=200 mL/hr×3 hr=600 mL

Question 15

What is the conversion factor for converting kg to lb?

Answer 15

lb=kg×2.2

Question 16

What does “mcg” stand for?

Answer 16

Microgram

Question 17

What is the formula for converting grams to milligrams?

Answer 17

mg=g×1000

Question 18

What does “p.r.n.” mean in medical terms?

Answer 18

As needed (derived from Latin, pro re nata).

Question 19

What is the importance of avoiding ambiguous abbreviations in prescriptions?

Answer 19

To prevent medication errors and ensure patient safety.

Question 20

What does “t.i.d.” stand for?

Answer 20

Three times a day (derived from Latin, ter in die).

Question 21

What is the formula for calculating infusion time if the total volume is 1,200 mL and the flow rate is 300 mL/hr?

Answer 21

infusion time = 1200 ml / 300 ml/hr = 4 hr

Question 22

1 kilogram = 1,000 grams
1 kilogram = 2.2 pounds

Answer 22

1 liter = 1,000 milliliters
1 gram = 1,000 milligrams

Question 23

1 tablespoon = 15 milliliters

Answer 23

1 pound = 454 grams

Question 24

1 milligram = 1,000 micrograms
1 grain = 64.8 milligrams

Answer 24

1 ounce = 28.35 grams
1 teaspoon = 5 milliliters

Question 25

Q1. How many kilograms are there in 3,450 grams?

Answer 25

There are 1,000 grams in 1 kilogram.

Therefore, we need to divide 3,450 grams by 1,000 to give us the value in kilograms.

3,450 / 1,000 = 3.45 kilograms.

Question 26

Q2. How many micrograms are there in 459 grams?

Answer 26

There are 1,000 micrograms in 1 milligram; and 1,000 milligrams in 1 gram.

Therefore, to convert 459 grams to micrograms, we simply need to multiply by 1,000,000 (1,000 x 1,000).

459 x 1,000,000 = 459,000,000 micrograms.

Question 27

Q3. How many grams are there in 7 pounds?

Answer 27

There are 454 grams in 1 pound, meaning 7 pounds is the same as 3,178 grams.

Question 28

Q4. How many tablespoons are there in 105 milliliters?

Answer 28

One tablespoon is the same as 15 milliliters.

Therefore, 105 milliliters is the same as 7 tablespoons.

Question 29

Q5. How many grains are there in 325 milligrams?

Answer 29

One grain is the same as 64.8 milligrams.

Therefore, 325 milligrams / 64.8 milligrams = 5 grains.

Question 30

Q6. If I have 4 ounces and 1.4 kilograms, how many grams do I have in total (rounded to nearest whole number)?

Answer 30

First, we need to convert both values to grams, and then add both values together.

One ounce is the same as 28.35 grams, so 4 ounces is the same as 113.4 grams.

There are 1,000 grams in 1 kilogram, so 1.4kg is the same as 1,400 grams.

In total, then, there are 1,400g + 113.4g = 1,513.4 grams in total. As we are asked to round to the nearest whole number, the answer is 1,513 grams.

Question 31

Q7. Convert 4 teaspoons and 8 tablespoons to liters.

Answer 31

One teaspoon is the same as 5mL, meaning that 4 teaspoons = 20mL

One tablespoon is the same as 15mL, meaning that 8 tablespoons = 120mL

In total, then, we have 140mL.

However, the question asks us to answer in liters.

Therefore, we need to divide 140mL / 1,000 = 0.14 liters.

Question 32

Q8. How many micrograms are there in 2.2 pounds?

Answer 32

2.2 pounds is the same as 1 kilogram.

1 kilogram = 1,000 grams = 1,000,000 milligrams = 1,000,000,000 micrograms

In each case, we multiply by 1,000 – first grams, then milligrams, then micrograms.

Question 33

Q9. How many ounces are there in 3,000 grams (rounded to the nearest whole number)?

Answer 33

There are 28.35 grams in 1 ounce.

Therefore, 3,000 grams / 28.35 grams = 105.8, or 106 ounces when rounded up to the nearest whole number.

Question 34

Q10. Approximately how many grains are there in 1 pound?

Answer 34

1 pound is the same as 454 grams, or 454,000 milligrams.

1 grain is the same as 64.8 milligrams.

Therefore, we need to divide the number of milligrams in 1 pound by the number of milligrams in 1 grain, to give us the final answer in grains.

454,000 / 64.8 = 7,006 grains in 1 pound, when rounded to the nearest whole number.