© Jones & Bartlett Learning, LLC Chapter© Jones2 & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & BartlettSystems Learning, LLC of Measure© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION % C OBJECTIVES © Jones & Bartlett. Learning, LLC © Jones & Bartlett Learning, LLC 789NOT FOR SALE—. OR DISTRIBUTIONUpon completion of this chapter,NOT FORthe technician SALE OR student DISTRIBUTION will be able to: 4 5 6 X • Express metric measures correctly. © Jones & Bartlett Learning, LLC • Convert measures© Jones within & Bartlett the metric Learning, system LLC accurately. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION • Identify symbols within all systems and identify their equivalent. • State the apothecaries’ measures commonly used in the © Jones & Bartlettprac ticeLearning, of pharmacy. LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION • Identify measures in the household system used in the practice of pharmacy. TERMS • State the common household equivalents in the © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC • 24-hour time metric system. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION • Apothecaries’ • Convert approximate equivalents between the metric, system apothecaries’, and household systems. • Avoirdupois © Jones & Bartlettsystem Learning, LLC • Become familiar© Jones with & milliequivalents, Bartlett Learning, units, LLC and NOT FOR •SALEGram OR DISTRIBUTION internationalNOT units FOR of measur SALE e.OR DISTRIBUTION • Household • Convert traditional 12-hour time to 24-hour time (military system or international time) and vice versa. • Liter © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Meter • NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION • Metric system © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 37 © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. 38 Pharmaceutical Calculations for the Pharmacy Technician © Jones & Bartlett Learning, LLCMedication is primarily manufactured,© Jones & ordered, Bartlett and Learning, prepared in LLC the metric system. NOT FOR SALE OR DISTRIBUTIONThe major focus of this chapterNOT is FOR to make SALE the metric OR system,DISTRIBUTION particularly as it is used in the practice of pharmacy, and converting measures within this system, habit to the technician student. The second focus of this chapter is to familiarize the technician student with the household system of measure and conversions between it and the metric system. A brief review of the apothecaries’ system is included. The apothe- © Jonescaries’ & systemBartlett has Learning, been almost LLCtotally replaced by the metric© system, Jones but & some Bartlett med- Learning, LLC NOT FORications SALE are still OR being DISTRIBUTION ordered in grains, and some manufacturersNOT FOR continue SALE to label OR DISTRIBUTION certain medications in grains. The avoirdupois system will also be mentioned in rela- tion to bulk and stock powdered chemicals and drugs. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTIONMetric System NOT FOR SALE OR DISTRIBUTION metric system The deci- The metric system of measure was formulated in France in the late 18th century. Its mal system of measure widely use in the United States was legalized (but not made mandatory) in 1866. By act of used for prescribing and Congress in 1893, it became our legal standard of measure, and all other systems © Jones &administering Bartlett medication.Learning, LLChave been referred to it for© officialJones comparison & Bartlett (including Learning, the UnitedLLC States’ cus- NOT FOR SALE OR DISTRIBUTIONtomary system of measurement—pounds,NOT FOR SALE yards, OR and DISTRIBUTIONso on) ever since. It is accepted by scientists the world over because its tables are simple, because they are based on the decimal system of notation, and because the greater of two consecutive denom- inations of the same kind is always 10 times the lesser. © Jones Each& Bartlett table of Learning,the metric system LLC contains a definitive unit.© JonesThe meter & isBartlett the unit Learning, LLC liter, gram, NOT FORof length; SALE the OR ofDISTRIBUTION volume; and the of weight. SubdivisionsNOT FOR and SALE multiples OR DISTRIBUTION of these principal units commonly used in pharmacy, their relative values, and their corresponding prefixes are shown in Table 2.1. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE ORRules DISTRIBUTION of the Metric SystemNOT FOR SALE OR DISTRIBUTION % C 1. Arabic numbers are used to express quantities in the metric system. 789—. 2. Decimal fractions are used in the metric system. A zero should always be placed in front of the decimal when the quantity is less than 1 (e.g., 0.4 mg and not .4 mg). © Jones & Bartlett4 5 Learning,6 X LLCNo decimal point or zero should© Jones follow & a wholeBartlett number. Learning, LLC NOT FOR SALE1 OR2 3DISTRIBUTION– 3. The quantity is always writtenNOT before FOR the SALE abbreviation OR DISTRIBUTION or symbol (e.g., 60 mg, 0 • = + 0.55 mL; not mg 60 or mL 0.55). © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FORMetric SALE symbols OR are DISTRIBUTIONthe same in singular and plural; e.g., 1 mg,NOT 2 mg,FOR or 100SALE mg. OR In DISTRIBUTION selecting among unit dimensions (e.g., mg, g, kg), the choice is generally the unit that will result in a numeric value between 1 and 1000. For example, 500 g rather than 0.5 kg; 1.96 kg rather than 1,960 g; 750 mL rather than 0.75 L; or 750 mm or © Jones & Bartlett75 Learning, cm rather than LLC 0.75 meter. © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Measure of Length meter Base unit of length in The meter is the fundamental unit of this system. It has been determined as approx- the metric system. imately one ten-millionth part of the distance from the earth’s equator to the North © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. CHAPTER 2 • Systems of Measure 39 © Jones & BartlettTable 2.1 Learning,Prefixes andLLC Relative Values of the© Metric Jones System & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Prefix Meaninga Subdivisions − Micro- © JonesOne-millionth & Bartlett (10 6 )Learning, LLC © Jones & Bartlett Learning, LLC Milli- NOT One-thousandthFOR SALE OR (10 −DISTRIBUTION3) NOT FOR SALE OR DISTRIBUTION Centi- One-hundredth (10−2) Deci- One-tenth (10−1) ©Multiples Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOTDeka- FOR SALE OR10 DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Hecto- 100 (102) Kilo- 1000 (103) © Jones & BartlettMega- Learning, LLC1 million (106) © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Giga- 1 billion (109) a Times the basic unit. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Pole, and is in factNOT 39.37 FOR inches, SALE or a little OR more DISTRIBUTION than 1 yard. The denominations usedNOT FOR SALE OR DISTRIBUTION most commonly are the millimeter, centimeter, and meter. The common application of length in the practice of pharmacy involves patient height. Table 2.2 shows length equivalencies in the metric system. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC MeasureNOT FOR of SALE Volume OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION The liter is the fundamental metric unit of volume. The denominations used most liter Base unit of volume in commonly are the milliliter and liter. Table 2.3 shows volume equivalences in the the metric system. metric system. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALEMeasure OR DISTRIBUTION of Weight NOT FOR SALE OR DISTRIBUTION The fundamental unit of weight in the metric system is the gram. The denominations gram Base unit of weight in used most commonly in the practice of pharmacy are the microgram, milligram, the metric system. gram, and kilogram. Table 2.4 shows weight equivalencies in the metric system. For micrograms,© Jonesthe abbreviation & Bartlett mcg Learning,and the symbol LLC ␮g are both used in this© Jones & Bartlett Learning, LLC ␮ 1 text. Although theNOT symbol FOR gSALEis used OR in DISTRIBUTIONthe United States Pharmacopeia, theNOT FOR SALE OR DISTRIBUTION abbreviation mcg is widely used in pharmaceutical package labeling and in pre- scription writing. The term gamma (γ) is customarily used for microgram in bio- chemical literature. Prescriptions written in the metric system use Arabic numerals before the abbreviations© Jones & forBartlett the denominations Learning, (e.g.,LLC 6 g). Quantities of weight© Jones are usually & Bartlett Learning, LLC writtenNOT FOR as grams SALE and ORdecimals DISTRIBUTIONof a gram, and volumes as millilitersNOT and FOR decimals SALE OR DISTRIBUTION of a milliliter. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. 40 Pharmaceutical Calculations for the Pharmacy Technician © Jones & Bartlett Learning, LLC © Jones