1. Chapter 11
Objectives
Calculate dosages with the dosage formula and/or dimension analysis
Use drug labels to gather dosage information to calculate the supply on hand
Convert among systems to calculate dosages
Convert a drug order to the format of the supply on hand

2. Dosage Calculations Unit 11
This unit pulls together all the math skills reviewed & practiced previously in this text. Your task will be to determine the individual dose a client will receive
Unit 11

3. Page 235
Overview
This unit pulls together all the math skill you have reviewed and practiced previously in this text.
You task will be to determine the individual dose of medication a client will receive.
This is a common task for nurses.

4. Performing Dosage Calculations
Pages 237 – 238
Performing Dosage Calculations
In order to calculate an individual dose, you must know three important pieces of information: the desired dose, the dosage strength, and the medications’ unit of measure. These three items are given in each dosage calculation.
Term
Symbol
Meaning
Example
Dosage ordered or desired dose D
the amount of medication that the physician has ordered for the client
Give 500 mg
Dosage strength or supply on hand H
the amount of drug in a specific unit of measure
200 mg
unit of measure or quantity of unit Q
the unit of measure for the specific dosage strength or supply on hand
___ per 2 mL
Continue to next slide

5. Performing Dosage Calculations (Cont’d)
Page 238
Performing Dosage Calculations (Cont’d)
When using the dosage formula you must ensure that the medication information is in the correct place. This formula can be used for most medication orders and is useful to memorize:
desired or dosage ordered
Supply on hand
unknown
dosage x
quantity =
Continue to next slide
The formula is abbreviated as: D H x
Q = x

6. Performing Dosage Calculations (Cont’d)
Pages 238 – 240
Performing Dosage Calculations (Cont’d)
Rule 1: The D and the H must be in the same unit of measure
Rule 2: The Q and the medication given will be in the same unit of measure.
dosage (D)
supply on hand (H)
Medication
given x
quantity (Q) =

7. Dimensional Analysis Page 240
A detailed section on using dimensional analysis is in appendix D for your reference. It is also known as the multiplication method for solving conversions.
Examples – page – practice 1-2: Evens
Group Work – page – practice 1-2: odds

8. Using Drug Labels to Calculate Dosages
Page 244
Using Drug Labels to Calculate Dosages
Use the medication labels to complete calculations. The drug label will supply the dosage strength and the unit.
Examples – page – practice 3: Evens
Group Work – page – practice 3: odds