Apothecary Conversion

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Apothecary Conversion

• Pro Calc Nursing 131

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Apothecary/Metric Conversion

• There are three systems of measurement being used
  in medication administration.
• Metric
• Apothecary
• Household
• This tutorial discusses converting units from the
  apothecary system of measurement to the metric
  system.

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Apothecary/Metric Conversion

• In the metric system liquid volumes are measured
  in milliliters or liters. Weight is measured in
  micrograms, milligrams, grams, or kilograms.

1 liter
1000 milliliter
1 kilogram
1,000 grams
1,000,000 milligrams
1,000,000,000 micrograms
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Apothecary/Metric Conversion
In the apothecary system liquid volumes are
measured in quarts, pints, ounces, drams, and
minims. Weight is measured in grains.
1 quart
2 pints
32 ounces
256 drams
15,360 minims
1 ounce 437.5 grains
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Apothecary/Metric Conversion

• Our Example Problem
• Acetaminophen is available in mg.
• 10 gr of Acetaminophen must be prepared. How
  many mg of Acetaminophen should be prepared?

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Apothecary/Metric Conversion

• Here are the 5 basic steps to change from one
  unit to another

Step 1 - Identify that you need to convert
Step 2 Write down what you have
Step 3 Write down your equivalent fraction
Step 4 Reduce units

• Step 5 Perform the math

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Apothecary/Metric Conversion

• Our Example Problem
• Acetaminophen is available in mg. 10 gr of
  Acetaminophen must be prepared. How many mg of
  Acetaminophen should be prepared?

Step 1 Identify you need to convert The question
asks how of one type of unit should we prepare in
another type of unit.
Step 2 Write down what you have The quantity we
have our known quantity - is 10 gr of
Acetaminophen. Write this as a fraction with 1 on
the bottom.
10 gr 1

• (Writing the amount as a fraction will help us
  when we multiply later.)

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Apothecary/Metric Conversion

• Our Example Problem
• Acetaminophen is available in mg. 10 gr of
  Acetaminophen must be prepared. How many mg of
  Acetaminophen should be prepared?

Step 3 Relate the units An equivalency chart will
list how the units relate.
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Apothecary/Metric Conversion

• Conversions between Apothecary and Metric Units
• 32 fluid ounces 1 liter
• 16 fluid ounces 500 milliliters
• 8 fluid ounces 240 milliliters
• 1 fluid ounce 30-32 milliliters
• 1 fluid dram 5 milliliters
• 15-16 minims 1 milliliter
• 1 grain 60 mg

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Apothecary/Metric Conversion
Step 3 Relate the units An equivalency chart will
list how the units relate.
Our chart lists 1 grain 60 mg.

• We will write this equivalency as a fraction.

• We can write this fraction 2 ways

1 grain 60 mg
60 mg 1 grain
or
Because the fraction we wrote in step 2 has
grains on the top, our next fraction must have
grains on the bottom.
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Apothecary/Metric Conversion
Step 3 Relate the units

• We now have

10 grain 1
60 mg 1 grain
x
To convert we will need to multiply our fractions.
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Apothecary/Metric Conversion
Step 4 Reduce the units Cross off any matching
pairs of unit labels. The label left should be
what you want to find.

• We now have

• We now have

10 grain 1
60 mg 1 grain
x

• In this example the only unit left is mg which is
  what we want to find.

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Apothecary/Metric Conversion
Step 5 Perform the math
10 grain 1
60 mg 1 grain
x
10 x 60 mg
600 mg

(reduce any fractions)
1 x 1
1
(include the units)
600 mg
10 grains is equivalent to 600 mg.
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Apothecary/Metric Conversion

• Our Example Problem
• Acetaminophen is available in mg.
• 10 gr of Acetaminophen must be prepared. How
  many mg of Acetaminophen should be prepared?
• We should prepare 600 mg of Acetaminophen.

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Apothecary/Metric Conversion

• These are the steps we used.
• Determine the need to perform a metric conversion
  (having one type of
  unit apothecary- and want to know another type
  -metric)
• Write down the starting term
• Find an equivalent fraction for the units.
  
  Write the equivalent fraction down next to the
  starting term with the units you want to
  eliminate on the bottom
• Reduce the units (Eliminate only the words that
  match in the top and bottom of your fractions.)
  When you are finished you should have only the
  terms you are looking for left.
• Perform the math operations and reduce your
  answer. (In some calculations you may need to
  round as specified by your instructions.)

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Learning Center Apothecary/Metric
ConversionTutorial