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

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

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.

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

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

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) =

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 241-243 – practice 1-2: Evens Group Work – page 241-243 – practice 1-2: odds

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 244-247 – practice 3: Evens Group Work – page 244-247 – practice 3: odds