Medical Dosage Calculation Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton CHAPTER Tenth Edition A Dimensional Analysis Approach Parenteral Medications 9

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Directory Classroom Response System Questions Lecture Note Presentation

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Classroom Response System Questions

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #1 The prescriber ordered penicillin G 300,000 unit IM every 12 hours. The label reads 600,000 units per milliliter. How many milliliters will you administer to the patient?

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #1 Choices mL mL mL mL

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #1 Response mL mL mL mL

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #2 The prescriber has ordered 4 milligrams of the analgesic drug, butorphanol tartrate (Stadol), IM every four hours PRN. The ampule reads 2 mg per 2 mL. How many milliliters will equal 4 milligrams?

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #2 Choices 1.4 mL 2.5 mL 3.6 mL 4.7 mL

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #2 Response 1.4 mL 2.5 mL 3.6 mL 4.7 mL

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #3 The order: clindamycin 400 mg IM twice a day for 5 days. The label reads 150 mg/mL. How many milliliters will you administer to your patient?

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #3 Choices mL mL mL mL

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #3 Response mL mL mL mL

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #4 The order reads: a drug g IM three times a day. If the label states 10 milligrams per milliliter, how many milliliters will you prepare for the patient?

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #4 Choices mL mL mL mL

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #4 Response mL mL mL mL

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #5 The label on the vial reads: penicillin G 1,000,000 units. The instructions are as follows: Add 19.6 mL of sterile dilutent to stock solution 1 mL = 50,000 units. How many milliliters contains 100,000 units?

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #5 Choices 1.2 mL 2.3 mL 3.20 mL 4.40 mL

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #5 Response 1.2 mL 2.3 mL 3.20 mL 4.40 mL

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Lecture Note Presentation

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Learning Outcomes 1.Calculate doses for parenteral medications in liquid form. 2.Interpret the directions on drug labels and package inserts for reconstituting medications supplied in powdered form. 3.Label reconstituted multi-dose medication containers with the necessary information. 4.Choose the most appropriate diluent volume when reconstituting a multiple-strength medication. 5.Calculate doses of parenteral medications measured in units.

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Figure 9.1 Ampules.

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Figure 9.2 Vials.

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Parenteral Medications Supplied as Liquids

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton The prescriber ordered 3 milligrams of Dolophine (methadone hydochloride) subcut stat. The strength is 10mg per mL. How many milliliters would you administer to the patient? 3 mg = ? mL Example 1

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton The label reads 10 milligrams per milliliter. This strength will be used as the unit fraction 0.3 mL So, 0.3 milliliter contains 3 milligrams of methadone, and you would administer 0.3 milliliter of the drug to the patient. Example 1

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton The prescriber ordered gram of a drug IM stat. The strength is 1mg per mL. Calculate the number of milliliters of this solution you would administer. You want to convert grams to its equivalent in milligrams, and then change milligrams to milliliters g Example 2 ? mg? mL

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Because the strength is 1 mg = 1 mL, no further calculations are needed to determine that 2mg = 2 mL You would administer 2 milliliters of the solution IM, which would contain gram of the prescribed drug g = mg= 2 mg Example 2

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Example 3 Determine the quantity of solution to be withdrawn from the vial if the medication order reads 250 milligrams of 10% calcium chloride.

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton You want to convert 250 milligrams to milliliters gram The strength of “10%” means that 10 grams of calcium chloride are in 100 milliliters of solution. Example mg ? g? mL

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton So, you would withdraw 2.5 mL from the vial. 2.5 mL Example 3

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Parenteral Medications Supplied in Powdered Form

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Powdered Parenteral Medication Some parenteral medications are supplied in powdered form in sealed vials.The powder cannot be removed from these vials. You must add sterile water or saline (diluent) to the vial and dissolve the powder to form a solution. You then withdraw from the vial the liquid volume of prepared solution that contains the proper amount of the drug.

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Figure 9.38 Drug label for Pfizerpen. (Reg.Trademark of Pfizer Inc.Reproduced with permission.)

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Example 5 The prescriber ordered 150 mg of a drug IM stat. The directions on the 500 mg vial read, “Add 9.7 mL NS and the strength will be 100 mg/mL.” How many milliliters of the reconstituted solution will you administer?

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton You want to convert 150 mg to mL. Using the strength of 100mg/mL. So, you would administer 1.5 mL of the solution. Example 5

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Figure 9.8 Reconstitution of ceftriaxone.

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Heparin

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Example 4 The prescriber ordered: heparin 5,000 units subcut q12h. The label on the vial reads 10,000 units per milliliter. How many milliliters will you administer to the patient?

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton You want to convert 5000 units to milliliters. The label on the vial reads 10,000 units per milliliter, so the strength is 5,000 units = ? mL Example 4 (continued)

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton So, 0.5 milliliter contains 10,000 units of heparin and you would administer 0.5 milliliter of the solution to the patient subcutaneously. Example 4 (continued) 1 2

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Chapter Summary Medications supplied in powdered form must be reconstituted following the manufacturer’s directions. You must determine the best dosage strength when there are several options for reconstituting the medication.

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Chapter Summary After reconstituting a multiple-dose vial, label the medication vial with the dates and times of both preparation and expiration, storage direc- tions, your initials, and strength.

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton When directions on the label are provided for both IM and IV reconstitution, be sure to read the order and the label carefully to determine the necessary amount of diluent to use. Heparin is measured in USP units. Chapter Summary

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton It is especially important that heparin orders be carefully checked with the available dosage strength before calculating the amount to be administered. A tuberculin (1 mL) or a 0.5 mL syringe should be used when administering heparin. Chapter Summary

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Chapter Summary Heparin sodium and heparin flush solutions are different and should never be used interchangeably.