Chapter 5 Unit, Percentage, Milliequivalent, Ratio, Household and Apothecary Measures Objectives The learner will recognize dosages: Measured in Units Measured as Percentages Using ratio Strengths In milliequivalents In household measure International Units Measure drugs in terms of its actions not weight For example Heparin, Insulin, Penicillin Units is written in lower cases such as 2000 units Use commas only if if 5 numbers are used eg 45,000. Note -Previously accepted abbreviation (U) on Joint Commission (JC) Do Not Use list Percentage measures % % means part per 100 for example 100 mL of a 1% will contain 1g of drug. % is also used in Intravenous solution, the greater the % strength the stronger the solution. In solutions 5 represents the number of grams of drugs. Milliequivalent (mEq) measures Milliequivalent (mEq) is an exprssion of the number of grams of a drug contained in 1mL of normal solution. Milliequivalent (mEq) is also written in using Arabic numerals with space in-between. For example 60 mEq. Note that the E is upper case and the m&q are lower cases. mEq Dosages 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 Ratio strengths are primarily used to describe solutions, representing part of a drug per parts of solution. For example Solution of 1 : 100 contains one part drug to 100 parts solution Ratio are expressed using the simplest forms for example 5:10 ration can be reduced further to 1:2 Written separated using Arabic numbers followed by space, colon, space, and another Arabic number Household Measures One of the oldest drug measurement systems Volume measurements include ounce, tablespoon, teaspoon, dram and drop (Drops or gtt). 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 HouseholdAbbreviationMetric 1 Ounceoz30 mL 1 Tablespoontbsp15 mL 1 Teaspoontsp5 mL 1 Dropgtt1 mL Apothecary Measures Basically obsolete ( not used anymore) Only measure still seen is grain (gr) Seldom used Equivalent to 60 mg in metric system References Curran, A.Witt, M. (2014) Math for Meds, dosage and solutions. ( 11th ed). Cengage learning, Stamford, CT.