Systems of measurement objectives Apothecary system Metric system

Systems of measurement

objectives • Apothecary system • Metric system • Abbreviations

Apothecary systems • Apothecary system is one of the oldest systems of measurement. • Uses fractions, as opposed to decimals. • Is less accurate than the metric system.

Terminology apothecary system • the system used by an apothecary • a system of measurement used in pharmacy prior to the metric system • units of measure include minims, fluidrams, scruples, grains, ounces, and pounds

Apothecary Volume and Weight Equivalences

apothecary pound = 12 oz household pound = 16 oz

Conversions between the Apothecary and the Metric Systems • Use equivalent measures to convert between units in the apothecary system. • As a general rule, convert all quantities to the metric system as soon as possible.

Volume Equivalents

Volume Equivalents There actually 3. 75 m. L in 1 fluidram. However, convention dictates that 1 fluidram = 1 tsp = 5 m. L.

Volume Equivalents There actually 29. 57 m. L in 1 fluidounce, but 30 m. L is usually used

Weight Equivalents

Weight Equivalents Many manufacturers use 60 mg instead of 65 mg as the equivalent for 1 grain.

Terminology grain the smallest unit of measure in the apothecary system

Conversions between the Apothecary and the Metric Systems Converting Grains • The units of grains appears on nitroglycerin, along with milligram equivalent. • Most pharmacists use 1 gr = 65 mg, but some sources indicate 1 gr = 60 mg.

Metric system • • • Kg- Kilogram L- Liter mcg- microgram m. Eq- milliequivalant mg- milligram m. L- milliliter μg- microgram μgtt- micro drop gm-gram

Safety Note! Many manufacturers use 60 mg instead of 65 mg as the equivalent for 1 grain. Read the label to confirm the package contents.

Conversions between the Apothecary and the Metric Systems Converting Fluidounces

Remember 16 fl oz = 480 1 fl oz = 30 m. L

Lbs. to Kg • There are two methods that may be used to convert pounds to Kg: • Lbs. / 2. 2 = Kg • Therefore, if you need to convert Kg to Lbs: • Kg x 2. 2 = Lbs.

Metric Conversions • Kg, g, mcg • Lbs. to Kg • L to m. L

Kg, g, mcg • To convert if going from large value to smaller value, move the decimal point 3 places to the right for each conversion. • If going from smaller value to larger value, move the decimal point 3 places to the left for each conversion. • 3. 0 Kg = 3000 g • 3. 0 Kg = 3000000. = 3, 000 mg • 3. 0 Kg = 30000000 00. = • 3, 000, 000 mcg

L to m. L • 1 L = 1000. = 1, 000 m. L • 500 m. L = 500. =. 5 L

Conversions to mg • • 300 mcg = 3 mg 6 Kg = 6, 000 mg 14 g = 14, 000 mg 1, 000 mcg = 1 mg

Conversions to mcg • • 1 g = 1, 000 mcg 0. 452 mg = 452 mcg 0. 010 mg =10 mcg 0. 0006 Kg = 600, 000 mcg

Conversions to g • • • 0. 043 Kg = 43 g 100, 000 mcg =0. 1 g 1, 000 mg = 1 g 0. 075 mg =0. 000075 g 1, 500 mcg = 0. 001500 g 1 Kg = 1, 000 g

Conversions to Kg • • 1000 g = 1 Kg 1, 500 mg = 0. 0015 Kg 0. 042 mg = 0. 000000042 Kg 720, 000 mcg = 0. 72 Kg

Lbs. to Kg • 275 Lbs. = 125 Kg • 100 Lbs. = 45 Kg

Kg to Lbs. • 100 Kg = 220 Lbs. • 32 Kg = 70 Lbs.

L to m. L • • 2 L = 2, 000 m. L 0. 5 L = 500 m. L 1 L = 1, 000 m. L 0. 250 L = 250 m. L

m. L to L • 3, 000 m. L = 3 L • 1, 500 m. L = 1. 5 L • 500 m. L = 0. 5 L

m. L v. cc • • • A m. L and a cc have the same value. Therefore: 1 m. L = 1 cc 500 m. L = 500 cc 0. 5 cc = 0. 5 m. L

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