Med Math

Question 1

How do you convert kg to lbs?

Answer 1

You do ____(kg) x 2.2 = ___lbs
ie. 30kg x 2.2 = 66lbs

*Multiplication

Question 2

How do you convert lbs to kg?

Answer 2

___(lbs) / 2.2 = __kg
ie. 66lbs / 2.2 = 30kg

*Division

Question 3

How do you convert mg to grams?

Answer 3

1000mg = 1g
*Division
ie: 500mg and 1500mg
500mg / 1000 = 0.5g
1500mg / 1000 = 1.5g

Question 4

How do you convert grams to mg?

Answer 4

1g = 1000mg
*Multiplication
ie: 5g and 2.5g and 0.2g
5g x 1000 = 5000mg
2.5g x 1000 = 2500mg
0.2g x 1000 = 200mg

Question 5

1tsp = how many mL?

Answer 5

1tsp = 5mL

Question 6

1 ounce = how many mL?

Answer 6

1 ounce = 30 mL
ie. 2 ounces = 60 mL
60 x 0.034 = 2.04 ounces

Question 7

What is the formula for medication dosage calculation?

Answer 7

dose desires
___________ x volume

dose on hand

Question 8

Your patient is to receive Digoxin but is having trouble swallowing the tablets. The pharmacist sends up a liquid form that reads 0.5mg/2mL. If the order is for 0.125mg how much would you give?

Answer 8

0.125mg
________ x 2 mL = 0.5 mL would be given.

0.5mg

Question 9

Acetaminophen 60mg q4hr. Weight = 10kg. Safe dosage range = 10-15mg/kg/DOSE.
Is the ordered dose within the range?

Answer 9

10mg x 10kg = 100mg minimum per dose
15mg x 10kg = 150mg maximum per dose
The order is for 60mg per dose q4hr, so this dose is NOT in range. It is too low.

Question 10

Ticarcillin 4g IV q6hr. Weight = 121lbs. Safe dosage is 200-300mg/kg/DAY. Is the DAILY ordered dose in range?

Answer 10

A few steps:
1. 121lbs / 2.2 = 55kg
2. 24 hours in a day and order is q6hr –> 24/6= 4 doses in a day
3.
200mg x 55kg = 11000mg = 11000/1000 = 11g
300mg x 55kg = 16500mg = 16500/1000 = 16.5g
4. Order if for 4g four times a day (every 6hrs), so 4g x 4 doses = 16g/day
5. This order is within range, as the range is 11g-16.5g day