Chapter 9 Parenteral Medication Labels and Dosage Calculation

par·en·ter·al (pă-rĕn′tər-əl)adj. 1. Physiology Located outside the digestive tract. 2. Medicine Taken into the body or administered in a manner other than through the digestive tract, as by intravenous or intramuscular injection. Copyright © 2015 Cengage Learning®

Parenteral Routes • IV (intravenous) – Most common • IM (intramuscular) • Subcutaneous – Second most common • sub·cu·ta·ne·ous • (sŭb′kyo o-tā′nē-əs)adj. Located or placed just beneath the skin: subcutaneous tissue; a subcutaneous implant. • Intradermal • in·tra·der·mal • (ĭn′trə-dûr′məl)adj. Within or between the layers of the skin: an intradermal injection. Copyright © 2015 Cengage Learning® 9 -3

• Subcutaneous injections are administered in the fat layer, underneath the skin. Intramuscular injections are delivered into the muscle. Intradermal injections are delivered into the dermis, or the skin layer underneath the epidermis (which is the upper skin layer). Copyright © 2015 Cengage Learning® 4

Packaging • Parenteral medications are available in ampules, vials, prefilled syringes, bag solutions, and

Labels of Parental Solutions • The labels of oral parental solutions are very similar,

IM Solutions • Manufactured so average adult dosage is contained in a volume between

Subcutaneous Solutions • Manufactured so average adult dosage is contained in a volume between 0. 5 m. L and 1 m. L. • Most dosages prepared using 3 m. L or TB syringe. Copyright © 2015 Cengage Learning® 9 -9

IV Medication Preparation • Administration usually two-step procedure: 1. Prepare dosage 2. Dilute in

Solution Labels • Metric/SI (examples) – morphine sulfate 4 mg/m. L – digoxin 75 mcg/m. L – cefazolin 1 gram/50 m. L See Examples 1 & 2, p. 103 • Percent (examples) – 1% lidocaine – 10% calcium gluconate – 0. 45% sodium chloride (continues) Copyright © 2015 Cengage Learning® 9 -11

Solution Labels (cont’d) • Ratio (examples) – 5000 : 1 heparin – 2500 : 1 heparin – 1000 : 1 epinephrine • International unit (examples) – heparin: 5000 international units – Factor VIII: 4550 international units – Factor IX: 2300 international units (continues) Copyright © 2015 Cengage Learning® 9 -12

Solution Labels (cont’d) • m. Eq (examples) – 20 m. Eq potassium chloride (KCl)

Safety Point • Labels of most parenteral solutions are quite small. – Read with

Example 1 • Prescription for atropine 1/150 grains subcutaneously • Atropine vial labeled 0. 4 mg/m. L • How many m. L should be administered subcutaneously? (continues) Copyright © 2015 Cengage Learning® 9 -15

Example 1 (cont’d) • • • Convert 1/150 grains to 0. 4 mg 1 gr = 60 mg (apothecary measure) Convert 1/150 gr to mg first. Then calculate m. L needed. Use basic formula: Copyright © 2015 Cengage Learning® 9 -16

Example 2 • Prescription for heparin 5000 units subcutaneously • Heparin vial labeled 10, 000 : 1 m. L heparin • How many m. L should be administered subcutaneously? (continues) Copyright © 2015 Cengage Learning® 9 -17

Example 2 (cont’d) • Use basic formula: Copyright © 2015 Cengage Learning® 9 -18

Example 3 • Prescription for morphine sulfate 2 mg IV • Morphine sulfate prefilled syringe contains 4 mg/m. L • How many m. L should be administered intravenously? (continues) Copyright © 2015 Cengage Learning® 9 -19

Example 3 (cont’d) • Use basic formula: Copyright © 2015 Cengage Learning® 9 -20

Example 4 • Prescription for promethazine sulfate 25 mg IV bolus • Promethazine sulfate

bo·lus ˈbōləs/ noun: bolus; plural noun: boluses 1. a small rounded mass of a substance, especially of chewed food at the moment of swallowing. 2. a type of large pill used in veterinary medicine. 3. Medicine 4. a single dose of a drug or other medicinal preparation given all at once. Copyright © 2015 Cengage Learning® 22

Example 4 (cont’d) • IV drug resource states each 12. 5 mg of promethazine sulfate should be diluted with 5 m. L normal saline for injection prior to administration via IV bolus. • How many total fluid and medication bolus m. L should be administered intravenously? (continues) Copyright © 2015 Cengage Learning® 9 -23

Example 4 (cont’d) • Each 12. 5 mg requires 5 m. L normal saline dilution • To dilute 25 mg requires 10 m. L of normal saline • 10 m. L normal saline + 1 m. L (25 mg) medication = 11 m. L total volume Copyright © 2015 Cengage Learning® 9 -24

Example 5 • Prescription for 2550 international units Factor IX concentrate intravenously each day • Pharmacy supplies Factor IX in concentration of 250 international units/5 m. L (continues) Copyright © 2015 Cengage Learning® 9 -25

Example 5 (cont’d) • How many m. L should be administered per intravenous bolus?

Example 5 (cont’d) • Use basic formula: Copyright © 2015 Cengage Learning® 9 -27

• Work through each of the problem sets in Chapter 9 in your text. Put your work in your notebook. • Take the Summary Self Test in your notes. • Take the Chapter 9 On. Line Quiz and report your results. Copyright © 2015 Cengage Learning® 28