Systems of measurement

1. Systems of measurement

2. objectives • Apothecary system • Metric system • Abbreviations

3. 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.

4. 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

5. Apothecary Volume and Weight Equivalences

6. Apothecary Volume and Weight Equivalences

7. Apothecary Volume and Weight Equivalences

8. apothecary pound = 12 oz household pound = 16 oz

9. 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.

10. Volume Equivalents

11. Volume Equivalents There are actually 3.75 mL in 1 fluidram. However, convention dictates that 1 fluidram = 1 tsp = 5 mL.

12. Volume Equivalents There are actually 29.57 mL in 1 fluidounce, but 30 mL is usually used

13. Weight Equivalents

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

15. Terminology grain the smallest unit of measure in the apothecary system

16. 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.

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

18. 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.

19. Conversions between the Apothecary and the Metric Systems Converting Fluidounces

20. Remember 16 fl oz = 480 1 fl oz = 30 mL

21. 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.

22. Metric Conversions • Kg, g, mg, mcg • Lbs. to Kg • L to mL

23. Kg, g, mg, 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 = 3000 g • 3.0 Kg = 3000000. = 3,000,000 mg • 3.0 Kg = 30000000 00. = • 3,000,000,000 mcg

24. L to mL • 1 L = 1000. = 1,000 mL • 500 mL = 500. = .5 L

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

26. Conversions to mcg • 1 g = 1,000,000 mcg • 0. 452 mg = 452 mcg • 0.010 mg =10 mcg • 0.0006 Kg = 600,000 mcg

27. 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

28. Conversions to Kg • 1000 g = 1 Kg • 1,500 mg = 0.0015 Kg • 0.042 mg = 0.000000042 Kg • 720,000,000 mcg = 0 .72 Kg

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

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

31. L to mL • 2 L = 2,000 mL • 0.5 L = 500 mL • 1 L = 1,000 mL • 0.250 L = 250 mL

32. mL to L • 3,000 mL = 3 L • 1,500 mL = 1.5 L • 500 mL = 0.5 L

33. mL v. cc • A mL and a cc have the same value. • Therefore: • 1 mL = 1 cc • 500 mL = 500 cc • 0 .5 cc = 0.5 mL

34. Thank you!!