1. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Chapter 3 Metric, Apothecary, and Household Systems of Measurement

2. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Metric System Weight equivalents –1 g = 1000 mg –1 mg = 1000 mcg A gram is greater than a milligram, which is greater than a microgram.

3. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Grams to Milligrams and Milligrams to Grams Quick Method Write order Write equivalents measure needed Show which way decimal point should move by drawing arrow Make open part of arrow always face larger measure Remember equivalent 1 g = 1000 mg

4. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question The physician has order 0.4 g of medication. How many milligrams is contained in this medication? A. 4 B. 40 C. 400 D. 4000

5. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer C. 400 You want to convert grams to milligrams: 0.4 g > 400 mg. The arrow tells you to move the decimal point three places to the right.

6. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Milligrams to Micrograms and Micrograms to Milligrams Quick Method Write order Write equivalents measure needed Show which way decimal point should move by drawing arrow Make open part of arrow always face larger measure Remember equivalent 1 mg = 1000 mcg

7. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question Is the following statement true or false? 4 mg is equal to 4000 mcg

8. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer True You want to convert milligrams to micrograms: 4 milligrams > 4000 mcg. The open part of the arrow faces the larger measure.

9. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Apothecary System Gradually replaced by metric system Equivalents between metric and apothecary system not exact Roman numerals designate amounts Grain only solid dosage

10. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Grain Generally 60 mg = 1 gr EXCEPTIONS 65 mg = 1 gr –Acetaminophen (Tylenol) –Aspirin Metric gram (g; gm; Gm) confused with grain (gr) WRITE OUT word “grain”

11. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Household Abbreviations Used for medications administered at home Examples –Pint –Quart –Teaspoon –Tablespoon

12. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Conversions Among Liquid Measures

13. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question The order is to administer 10 mL of a medication. How many teaspoons of this medication will you administer to the patient? A. ½ B. 1 C. 1½ D. 2

14. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer D. 2 1 teaspoon is equivalent to 5 mL. ½ teaspoon is equivalent to 2.5 mL. 1½ teaspoon is equivalent to 7.5 mL. 2 teaspoons is equivalent to 10 mL.

15. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Temperature Convert Fahrenheit to Centigrade –C = (F – 32) × 5/9 Convert Centigrade to Fahrenheit –F = (C × 9/5) + 32

16. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question The client’s temperature using an oral electronic thermometer is 40 centigrade. What is the client’s Fahrenheit temperature? A. 100 B. 101 C. 103 D. 104

17. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer D. 104 When the Celsius reading is 40: F = (40 × 9/5) + 32 = (72) + 32 = 104