Common Terms/Basic Math Review for NUR 373

You need to know this!

1 kilogram (kg) = 1000 grams (g)

1 kilogram (kg) = 2.2 pounds (lb) example: 100kg man = 220 lb 100 X 2.2

kg to pounds multiply; lbs to kgs divide

1 gram (g) = 1000 milligrams (mg) example: 0.5 g = 500 mg 0.5 X 1000

1 milligram (mg) = 1000 micrograms (mcg)

1 gram = 1000 mg=15 grains

60 mg = 1 grain

1 liter (L) = 1000 milliliters (mL) Never use cc (cubic centimeters) which is = to mL

Common Household and Apothecary Measures and Metric Equivalent

1 ounce (oz) = 30 milliliters (mL)

16 ounces (oz) = 1 pound (lb)

1 tablespoon (T, TBS, tbs) = 15 milliliters (mL)

1 teaspoon (t, TSP, tsp) = 5 milliliters (mL)

1 dram (dr) = 4 milliliters (mL)

1 drop (gtt) = 1 milliliters (mL)

International Units

Drugs measured in units such as insulin and heparin always have the word units written out. There is no safe abbreviation for units. It is considered an unsafe abbreviation to use “u”.

International units measure a drug by its action rather than its weight.

Common Dosage Administration Schedules

Become familiar with military time : ex. 1am is 0100 and 1pm is 1300

Before meals = AC/ac

After meals = PC/pc

At bedtime = hs ( considered unsafe abbreviation by ISMP)

Every day/once a day = daily (qd or QD considered unsafe abbreviation)

When needed/when required = prn

Every morning = qAM

Two times a day = BID or bid

Every 12 hours = q12h

Every 6 hours = q6h

Four times a day = QID or qid

Every 8 hours = q8h

Three times a day = TID or tid

Every other day = every other day (qod considered unsafe abbreviation)

Give immediately = STAT

Other Common Abbreviations/Terms (more on p. 330/331 of Taylor text)

PO (per os) = by mouth, orally: write PO, by mouth or orally

ID = intradermal

Subcutaneous = use subcut or write out subcutaneous (SQ considered unsafe abbreviation)

Intramuscular = IM

Intravenous = IV

Sublingual = SL or write out sublingual

Out of bed = OOB

Bed rest = BR

Bathroom privileges = BRP

Weight bearing = WB

Non weight bearing = NWB

Out of bed as desired = OOB ad lib

Short of breath = SOB

Fever of undetermined origin = FUO

Decimals/Fractions

Always place zero (0) in front of decimal if no whole number (0.5)

Never add extra zeros (0) at end of decimal fractions (4; not 4.0)

RELATIVE VALUES of DECIMALS:

0.1  = 1/10 0.01 = 1/100 0.001 = 1/1000

Example: (TENTHS) 0.6 > 0.5 we know this because: 0.6 = 6/10 > 0.5 = 5/10

5.8 > 4.9 we know this because the whole number to the left of the decimal (5) is larger than the whole number to the left of the decimal of the other number (4)

Example: rounding to the nearest 10th

0.52 = 0.5 0.55 = 0.6

Example: (HUNDREDTHS) 0.58 = 58/100 > 0.52 = 52/100

Example: rounding to the nearest 100th

0.586 = 0.59 0.524 = 0.52

Example : (THOUSANDTHS) 0.5895 > 0.5894

Example: rounding to the nearest 1000th

0.5867 = 0.587

Example: common mg dosage is 0.25 and 0.125 0.25 > 0.125

25/100 > 125/1000 eliminate decimals

250/1000 > 125/1000 common denominator

25/100 > 12.5/100 common denominator

ADDITION of DECIMALS : line up decimal points

Example: 0.25 + 0.125 = 0.375 0.250 add zeros to make equal length

+0.125

0.375

Example: You have just given two tablets of medication and each tablet is labeled 1.25mg. How many mg have you given?

SUBTRACTION OF DECIMALS: same rules as addition

Example: 0.25 – 0.125 = 0.125 0.250

- 0.125

0.125

Example: Your patient is to receive 15 mg of a drug, but you only have 7.5 mg. How many more mg do you need?

MULTIPLICATION of DECIMALS – Proper placement of the decimal point in the product is of utmost importance. The decimal point of the product is placed the same number of places to the left in the product as the total of numbers following the decimal points in the fractions multiplied :

Example: 1.5 X 0.2 = 0.3 1.5 total of 2 decimal points following = 0.3

X 0.2

.3

Example: 1.5 X 0.06 1.5 total of 3 decimal point following = 0.09

X 0.06

.09

Example: 0.21 X 0.32 .21 indent 2nd number of the multiplication

X .32

42 total of 4 decimal points following =

63

0.0672 0.0672

Example: You are to give 3 tablets labeled as 0.04 mg each. How many mg would you administer?

DIVISION OF DECIMALS

Change the division problem into a fraction with a numerator and denominator:

Example: 0.25 ÷ 0.125 = 0.25

0.125

Elimination of decimal points: to eliminate decimal points move them the same number of places to the right in a numerator and denominator until eliminated from both. Zeros may have to be added to accomplish this:

Example : 0.25 = 250 = 2

0.125 125

Example : 0.3 ÷ 0.15 = 0.3 = 30 = 2

0.15 15

Once the decimal points are eliminated the second step is to reduce the number as far as possible using the greatest common denominator (GCD) : the largest number that will divide in both N/D

Example: 250 Use 5 as GCD = 50 can be reduced again by 5 or 25

125 25

Example : 30 Use 5 or 15 as GCD

15

Example: 1.4 ÷ 7 = 14 Use 7 as GCD and then reduce again by 2: 2/10 = 1/5 = 0.2

70

Reducing Zeros : numbers that end in a zero or zeros can be reduced by crossing off the same number of zeros in the numerator and the denominator

Example : 8000 = 8000 = 8

4000 4000 4

Fraction Equations:

Calculations are made by dividing the numerators by the denominators.

Example: 2 = 2÷5 = 0.4

5

Example: Multiply the numerators and then divide by the denominators

2 X 1 = 2 = 1 = 0.2

5 2 10 5

2 X 1 ÷ 5 ÷ 2 = 0.2

Example : 2 X 3 = reduce to 1 X 3 = 3 = 0.3

5 4 5 2 10

Example: 1000 X 500 = 4 (reduce by zeros and GCD)

1500 250 3

Decimal Fraction Equations: elimination of decimal points and reducing of fractions. Need to be very careful eliminating decimal points correctly

0.3 X 2.1 = 3 X 210 = reduce to : 1 X 42 = reduce again answer is 3.5

1.2 0.15 12 15 4 3

Curren, A. (2010). Dimensional analysis for meds (4th Ed.). New York: Delmar, Cengage

Learning.