pharmaceutical pharmacology medicine drugs

1. © 2009 Delmar, Cengage Learning
Chapter 5
Unit, Percentage, Milliequivalent, Ratio,
Household and Apothecary Measures

2. © 2009 Delmar, Cengage Learning
International Units
• Measure drug’s action
– Not weight

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International Units
• Not abbreviated
• Previously accepted abbreviation (U) on
Joint Commission (JC) “Do Not Use” list

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International Units
• Written using Arabic numbers followed by
space and word “unit”
• Commas not used unless at least five digits
• E.g., 6 units, 1000 units, 250,000 units

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International Units
• Common medications expressed in units
– Insulin and heparin

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Percentage Measurements
• Indicate parts per hundred
• Greater the percentage, stronger the
solution

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Percentage Measurements
• Used primarily in intravenous (IV)
solutions
• Also used in topical, ophthalmic, and optic
solutions
– For skin, eyes, and ears

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Percentage Measurements
• In solutions, represent number of grams of
drug per 100 milliliters of solution
– E.g., 100 mL of 5% solution contains 5 g of drug

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Percentage Measurements
• Dextrose and sodium chloride
– Most common percentage dosages
– Dextrose dosages written as whole number
• E.g., 5% dextrose in water (D5W)
– Sodium chloride dosages written as decimal fraction
• E.g., 0.45% sodium chloride

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Milliequivalent (mEq)
Measurements
• Expression of number of grams of drug in 1
mL of normal solution

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mEq Dosages
• Written using Arabic numbers followed by
space and abbreviation mEq

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mEq Dosages
• Used in variety of oral and IV solutions
– E.g., potassium chloride most commonly used
• 20 milliequivalents written as 20 mEq KCl

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Percentage and mEq Measures
• Solutions with combination of percentage
and mEq measures
– E.g., 5% dextrose in water with 0.45% sodium chloride
and 20 milliequivalents of potassium chloride written
as 20 mEq KCl in D 5%/0.45% NaCl

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Ratio Measures
• Strengths primarily used to describe
solutions
• Written using Arabic numbers followed by
space, colon, space, and another Arabic
number
• Solution of 1 : 100 contains one part drug to
100 parts solution

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Household Measures
• One of the oldest drug measurement
systems
• Volume measurements include ounce,
tablespoon, teaspoon, and drop

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Household Measures
• Drop is integral part of small volume
medication preparation
– Including those for eye, ear, and nose
• Drop used almost exclusively with
medications with attached dropper

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Household/Metric Equivalents
Household Abbreviation Metric
1 Ounce oz 30 mL
1 Tablespoon tbsp 15 mL
1 Teaspoon tsp 5 mL
1 Drop gtt 1 mL

18. © 2009 Delmar, Cengage Learning
Apothecary Measures
• Basically obsolete
• Only measure still seen is grain (gr)
– Seldom used
– Equivalent to 60 mg in metric system