Metric Equivalencies for Weight
|
1 kilogram |
= 1000 g |
|
1 gram |
= 1000 mg |
|
1 miligram |
= 1000 mcg |
When converting within the metric system, you can simply move the decimal point three places to the left or right, depending whether you are changing to a larger or smaller unit of measure. The method I have found useful is to consider the alphabet:
The letter L represents larger unit, the letter S represent smaller unit. To convert from large to small, the decimal moves three places in the direction you move from L to S, or to the right. Example 1 illustrates that move. To convert from a smaller unit to a larger one, the decimal moves three places in the direction you move from S to L, or to the left. Example 2 illustrates that move.
Example 1: change 200mg to mcg
200 mg goes to 200,000mcg
Example 2: change 200mg to g
200. 0 mg goes to 0.2 g
Metric Abbreviations for Volume
|
liter |
L |
|
milliliter |
mL |
Metric Equivalencies for Volume
|
1000 mL |
= 1 L |
The Apothecary System uses grains, drams and ounces as units of weight. Lowercase Roman numerals are used when amounts are greater than one; fractions are used when amounts are less than one. The abbreviation precedes the amount, for example, grains x or grains 1/150. One-half may be expressed as ss, thus: iiiss = 3 1/2.
Apothecary Abbreviations
|
grain |
gr |
|
dram |
dr |
|
ounce |
oz |
Equivalencies that should be memorized when converting from apothecary to metric are:
Apothecary & Metric Equivalencies
|
1 ounce |
30 mL |
|
1 dram |
4 mL |
|
1 grain |
60 mg |
Household measures are commonly used to measure medications at home. Abbreviations and equivalencies follow.
Equivalencies
|
Household Measure |
Abbreviation |
Metric Measure |
Apothecary Measure |
|
1 cup |
C |
1 C = 240 mL |
= 8 oz |
|
1 tablespoon |
T (tbs) |
1 T = 15 mL |
|
|
1 teaspoon |
t (tsp) |
1 t = 5 mL |
|
|
drop |
gtt |
depends on size of drop |
|
|
pound |
lb |
2.2 lb = 1 kg |
1 lb = 16 oz |
Remember the five rights: The minimum standard of practice for medication administration is checking the “five rights” to provide patient safety.
Do I have the right drug?
Do I have the right patient?
Do I have the right dose?
Do I have the right time?
Do I have the right route?
Now add to this the sixth right...the right to refuse!
The Three Checks Prior to Administration of Medications
· taking off shelf
· taking out medication
· putting back on shelf
1 drop (gtt) = .06 milliliter (ml)
15 drops (gtts) = 1 milliliter (ml)
1 teaspoon (tsp) = 5 milliliters (ml)
1 tablespoon (Tbsp) = 15 milliliters (ml)
1 ounce (oz) = 30 milliliters (ml)
1 cup (c) = 240 milliliters (ml)
1 pint = 480 milliliters (ml)
1 quart = 960 milliliters (ml)
4 cups (c) = 960 milliliters (ml)
WEIGHTS AND MEASURES CONVERSION TABLE
METRIC WEIGHT MEASURE
1 Kilogram (Kg) = 100 grams (Gm) 1 Gram (Gm)
1 Gram (Gm) = .001kilogram (Kg)
1 Gram = 1000 milligrams (mg)
1 Milligram (mg) = .001 gram (Gm)
1 Milligram = 1000 Microgams (mcg)
1 Microgram (Mcg) = .001 Milligram (mg)
METRIC FLUID MEASURE
1 Liter (L) = 1000 milliters (ml)
1 Milliliter (ml) = .001 liter (L)
1 Milliliter (ml) = 1 cubic centimeter
APOTHECARY WEIGHT TO METRIC SYSTEM
1 grain (gr) = .065 gram = 60 milligrams (sometimes considered to be 64 to 65 milligrams)
WEIGHT CONVERSION
1 kg = 2.2 lbs
Basic Formula
Desired Dose x VolumeDose on Hand = VolumeDesired Dose
Dose on Hand
or
D x V = A
H
Flow Rates (gtt/min)
Flow Rate = Total Volume (mL) x Set Calibration (gtt/mL)
Time (min)
Flow Rate = mL/hr ¸ Division Factor
Division Factor = 60 ¸ calibration
Infusion Time
Infusion Time = Total Volume to be Infused
mL/hr being infused
Infusion Time = Total Volume to Infuse ÷ gtt / min x 60 mi
Set calibration
