Chapter 5 Unit, Percentage, Milliequivalent, Ratio, Household, and Apothecary Measures

International Units Measure drug’s action Not abbreviated Not weight Not abbreviated Previously accepted abbreviation (U) on Joint Commission (JC) “Do Not Use” list

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

International Units Common medications expressed in units Insulin Heparin

Percentage Measurements Indicate parts per 100 Greater the percentage, stronger the solution

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

Percentage Measurements In solutions, represent number of grams of drug per 100 mL of solution e.g., 100 mL of 5% solution contains 5 g of drug e.g., 100 mL of 0.9% solution contains 0.9 g of drug

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

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

mEq Dosages Written using Arabic numbers followed by space and abbreviation mEq Used in variety of oral and IV solutions e.g., potassium chloride most commonly used 20 milliequivalents written as 20 mEq KCl

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

Ratio Measures Strengths primarily used to describe solutions Written using Arabic numbers followed by space, colon, space, and another Arabic number

Ratio Measures Ratio strengths represent parts of drug per parts of solution Less solution drug is dissolved in, stronger the solution Solution of 1 : 100 contains one part drug to 100 parts solution

Household Measures One of the oldest drug measurement systems Volume measurements include ounce, tablespoon, teaspoon, dram, and drop Volume of drop depends on size of dropper being used

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

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

Apothecary Measures Obsolete and should not be used