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 Preparation of Solutions 8

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 If a 25% solution is diluted, what might be the strength of the resulting solution?

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 1.50% 2.25% 3.10% 4.75%

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 1.50% 2.25% 3.10% 4.75%

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 If a 1:69 solution is diluted, what might be the strength of the resulting solution?

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 1.1:30 2.1:90 3.2: :12

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 1.1:30 2.1:90 3.2: :12

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 If 1 liter of a solution contains 100 grams of pure drug, what is the strength of this solution as a fraction, ratio, and as a percentage?

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 1.1/100 strength, 1:100, 1% 2.1/1000 strength, 1:1000, 0.1% 3.½ strength, 1:2, 50% 4.1/10 strength, 1:10, 10%

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 1.1/100 strength, 1:100, 1% 2.1/1000 strength, 1:1000, 0.1% 3.½ strength, 1:2, 50% 4.1/10 strength, 1:10, 10%

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 strength stated on a drug label is 100 mg/mL. Write this strength in the form of a percentage.

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 1.500% 2.50% 3.5% 4.10%

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 1.500% 2.50% 3.5% 4.10%

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 physician orders minoxidil (Rogaine) 2%; apply 2 mL to scalp b.i.d. How many milligrams of minoxidil will be applied to the scalp with each dose?

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 1.40 mg 2.4 mg 3.5 mg 4.2 mg

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 1.40 mg 2.4 mg 3.5 mg 4.2 mg

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.Describe the strength of a solution as a ratio, fraction and as a percent. 2.Determine the amount of solute (drug) in a given amount of solution. 3.Determine the amount of solution that would contain a given amount of solute (drug). 4.Do the calculations necessary to prepare a solution from a solute. 5.Do the calculations necessary to prepare solutions for irrigations, soaks, and nutritional feedings.

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 Strength of a Solution Examples of strength using stated units of measurement:

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 Solution strength can also be stated without explicit units of measurement. For example, a solution which is 1 part iodine in 2 parts of solution has strength of: Ratio Fraction Percent Strength of a Solution 1:2 50%

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 Measure the Amount of Drug (Solute) in either g or mL Measure the Amount of the Solution in mL Strength of a Solution 1:100 NaCl solution has 1 g NaCl in 100 mL of the solution 1/3 strength solution of Iodine has 1 mL of Iodine in 3 mL of solution. 7% magnesium sulfate solution has 7 g magnesium sulfate in 100 mL of solution

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 What is the strength of a 500 milliliter solution that contains 50 mL of iodine? The strength is 1:10, 1/10 strength, or 10% = 50 mL 500 mL 1 10 Find the 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 What is the strength of a 200 milliliter solution that contains 50 g of NaCl? The strength is 1:4, ¼ strength, or 25% = 50 g mL 4 1 Find the 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 How many grams of dextrose would you need to prepare 1000 milliliters of a 5% solution? Amount of solution is 1,000 milliliters. Strength is 5% Find the amount of solute in a given amount of solution of known strength This means

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 need 50 grams of dextrose to prepare 1,000 milliliters of a 5% solution. 50 g Convert 1,000 mL of solution to g of dextrose

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 How would you prepare 250 milliliters of a 1/2% creosol solution? Creosol comes in liquid form. Amount of solution is 250 milliliters. Finding the Amount of Solute This means Strength is ½% or 0.5%

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 So, 1.25 milliliters of creosol is diluted with water to 250 milliliters of solution. =1.25 mL Creosol Convert 250 mL solution to ? mL of Creosol =? mL of Creosol

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 the 40 grams of pure drug to milliliters of solution. 40 g = ? mL Find the amount of solution of known strength containing a given amount of solute How many milliliters of a 20% magnesium sulfate solution will contain 40 grams of the solute magnesium sulfate?

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 In a 20% solution, there are 20 grams of solute per 100 mL of solution. So, the strength is mL So, 200 mL of a 20% magnesium sulfate solution contains 40 g of magnesium sulfate.

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 How many ounces of full-strength Sustacal are needed to make 16 ounces of ¼ strength Sustacal? Finding the Amount of Solute

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 = 4 oz So, 4 oz of full-strength Sustical are needed to make 16 ounces of ¼ strength Sustical. 16 oz Solution = ? oz Sustical = ? oz Sustical 1 4

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 The strength of a solution is the ratio of the amount of solute dissolved in the solution to the total volume of the solution. The strength of a solution may be expressed in the form of a ratio,fraction,or percentage. A 1/2 strength solution is a 1:2 or a 50% solution, and should not be confused with a 1/2 % solution.

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 The amount of solute dissolved in the solution should be expressed in milliliters if the solute is a liquid. The amount of solute dissolved in the solution should be expressed in grams if the solute is a solid or powder. The volume of a solution should be expressed in milliliters.

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 To determine the amount of solute contained in a given amount of a solution of known strength, use the strength as the known equivalence. To determine amount of a solution of known strength containing a given amount of solute, use the strength as the known equivalence.

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 strength of a particular solution may be written in many different forms. The following strengths are all equivalent: With stated Units of Measurement Rates Equivalence 500 mg = 1 mL 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 Without stated Units of Measurement Fraction1/2 strength Ratio1:2 Percentage50% Chapter Summary