1. MEDICATION MATH

2. Where do we start?
Lets start by looking at a very valuable resource that is available to you
This type of math requires practice and repetition as there are many different aspects of it. This web site will provide you modules to learn from and much practice.
Remember : MATH PROBLEMS ACCOUNT FOR 10 QUESTIONS ON EACH TEST!!!!!

3. Commonly Used Abbreviations
There are endless amounts of abbreviations in nursing that you must learn and be held accountable for.
Not knowing an abbreviation can cause a medication error and ultimately the death of your patient.

4. Commonly Used AbbreviationsAC
Ad lib
BID* G
Gtt ID IM IV Kg
Mcg
mEq Mg
Before meals
As desired
Twice per day
Gram
Drop
Intradermally (TB)
Intramuscular (FLU)
Intravenously
Kilogram
Microgram
Milliequivalent (K+)
Milligram

5. Commonly Used AbbreviationsmL
NKDA
NPO a p pc PO
PRN
Q2H, Q4H, Q6H, etc c s SL
Milliliter
No known drug allergies
Nothing by mouth
Before
After
After meals
By mouth
As needed, when necessary
Every _ hours
With
Without
Sublingual (Nitro)

6. Commonly Used Abbreviations
STAT
Subq, Subcut*
Supp
Susp
Tbs, Tbsp, T
TID
Tsp
ARE ALL ABBREVIATIONS SAFE? 
Immediately
Subcutaneous (Insulin)
Suppository
Suspension
Tablespoon
Three times a day
Teaspoon

7. Prohibited Abbreviations
U or u IU QD
QOD
Trailing zero (X.O mg)
Lack of leading zero (.X mg)
MS or MSO4
MgSO4
Unit
International Units
Every day
Every other day
Delete the trailing zero (X mg)
Insert a leading zero (O.X mg)
Morphine Sulfate
Magnesium Sulfate

8. The Metric System 1 mg = 1000 mcg 1 g = 1000 mg 1 kg = 1000 g
1 kg = 2.2 lbs
Traditionally, we would solve metric system problems by simply moving the decimal point.
In nursing, we must be cautious about the math we do so there is a formula based on ratio and proportion for working these problems.

9. The Metric System Problem 1: 40 mg = _ g
Step 1: Know your conversion (1000 mg = 1 g)
Step 2: Set up your problem using the following ratio and proportion template based on what you have vs what you need;
40 mg mg =
X g g
Step 3: Cross multiply and solve while not forgetting to label your work
1000X = 40 (now divide 40 by 1000)
X = 0.04 g

10. The Metric System
Medication is often given based on weight so it is important to know how to change pounds to kg.
Remember: 1 KG = 2.2 lbs
If you are given the problem in pounds you divide by 2.2. Example: 60 lbs/2.2 = 27.3 kg
If you are given the problem in KG you multiply by 2.2. Example: 15 kg x 2.2 = 33 lbs.
Remember: KG will ALWAYS be smaller than lbs!

11. The Metric System Let’s try a few together; 2.5 g = _ mg
150 mcg = _ mg
20 mg = _ mcg
90 lbs = _ kg
16 kg = _ lbs

12. Apothecary Measurements
Apothecary measurements are outdated but then again we also have some outdated physicians so these measurements MAY be seen.
If you see one it will be;
i grain = mg
gr1/2 = 30 mg
gr1/100 = 0.6 mg
X grain = 600 mg

13. Rounding Rules
The general rules for rounding medication calculations are as follows;
For adults, medication is rounded to the nearest tenth (2.1, 5.2, 7.7, etc.)
For children, medication is rounded to the nearest hundreth (2.12, 5.27, 7.77, etc)
Let’s talk about what this means…..

14. Metric Oral 1 Step Practice Problems
Now let’s put our ratio and proportion method to work in figuring out medication problems!
Here is your first problem;
Order: Synthroid 0.02 mg
On Hand (Label): 0.01 mg tablets
How do you set up and work this problem?

15. Metric Oral 1 Step Practice Problems
Let’s work it out;
Order: Synthroid 0.02 mg
On hand: Synthroid 0.01 mg tablets
THE WORK THE PROOF
0.02 mg mg mg mg
= =
X tab tab tabs tab
0.01 X = (0.02) = 2(0.01)
X = 2 tabs =0.02

16. Metric Oral 1 Step Practice Problems
Let’s do some more……….
Order: Diazepam 5 mg. On hand: Diazepam 10 mg scored tablets. How many tablets will you give?
Order: Voltaren 450 mg. On hand: Voltaren 150 mg tablets. How many tablets will you give?
Order: Clinoril 800 mg. On hand: Clinoril 400 mg tablets. How many tablets will you give?

17. Metric Oral 1 Step Practice Problems
Here is one that is SLIGHTLY different;
Order: KCL 20 mEq. Label: KCL 8 mEq/5 mL. How many mL will you give?
THE WORK THE PROOF
20 mEq mEq mEq mEq
= =
X ml mL mL mL
8X = 20(5) (5) = 12.5(8)
8X = = 100
X = 12.5 mL

18. Metric Oral 1 Step Practice Problems
ANY QUESTIONS ON THIS TYPE OF PROBLEM?

19. Metric Oral 2 Step Practice Problems
Sometimes a medication is ordered but what we have on hand is in a different metric equivalent.
This requires us to first convert our order to the metric equivalent we have on hand then solve for how much medication we must give.
These are step problems.

20. Metric Oral 2 Step Practice Problems
Let’s try one:
Order: Glucophage 1 g PO daily. On hand: Glucophage 500 mg tablets. How many tablets will you give?
What is Step 1?
What is Step 2?

21. Metric Oral 2 Step Practice Problems
Order: Glucophage 1 g PO daily. On hand: Glucophage 500 mg tablets. How many tablets
Step 1: Change g to mg because that is what we have on hand.
1 g g
=  X = 1000 mg (****THIS IS NOW WHAT IS ORDERED)
X mg mg
Step 2: Figure out how many tablets you need.
1000 mg mg THE PROOF:
= mg mg
X Tab Tab =
500X = tab tab
X = 2 Tabs = 500(2) =1000

22. Metric Oral 2 Step Practice Problems
Let’s do some more;
Ordered: Valium 0.01 g BID PO for a patient with anxiety. On Hand: Valium 5 mg tablets. How many tablets will you give?
Ordered: Lanoxin 0.25 mg every other day for CHF. On hand: Lanoxin 125 mcg tablets. How many tablets will you give?
Ordered: Dilantin 0.2 g BID PO for a patient with seizures. On Hand: Dilantin 100 mg capsules. How many capsules should you give?

23. Let’s Move On To IM Problems
IM calculations are essentially the same as the PO ones except you will be giving a specified amount of the medication in mL.
Let’s try one!
Order: Ativan 2 mg IM. On hand: Ativan 4 mg/ml. How many ml will you give?
2 mg 4 mg THE PROOF:
= mg mg
X ml ml =
4x = ml ml
X = 0.5 ml (1) = 4(0.5)
2 = 2

24. Let’s Move On To IM Problems
Let’s try some more IM problems:
Order: Morphine 10 mg IM. On hand: Morphine 15 mg/ml. How many ml will you give?
Order: Atropine 0.4 mg IM STAT. ON hand: Atropine 0.3 mg/0.5 ml. How many ml will you give?
Order: Compazine 25 mg Q4H IM. On hand: Compazine 10 mg/ml. How many ml will you give?

25. Time for questions……
Questions? More Examples? More Practice?