Class Scores Copyright 2016 Cengage Learning ALL RIGHTS

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Class Scores Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Class Scores Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Chapter 10 Oral Dosage of Drugs Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Chapter 10 Oral Dosage of Drugs Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Oral Medications • Come in variety of forms – Tablets – Capsules – Liquids

Oral Medications • Come in variety of forms – Tablets – Capsules – Liquids Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Unit Dosed Packaging Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Unit Dosed Packaging Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Take Note: • Some medications may not come in liquid form • Need to

Take Note: • Some medications may not come in liquid form • Need to be crushed or capsule opened • Prescription may be an alternate enteral route: nasograstric (NG), nasojejunal (NJ), gastrostomy Tube (GT), jejunum tube (JT), and percutaneous endoscopic gastrostomy (PEG) Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Tablets and Capsules • Supplied in strengths or dosages in which they are commonly

Tablets and Capsules • Supplied in strengths or dosages in which they are commonly prescribed – Only scored tablets are intended to be divided Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Pill Cutter Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Pill Cutter Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Tablets and Capsules Sustained-release capsules cannot be opened and mixed with food or fluid,

Tablets and Capsules Sustained-release capsules cannot be opened and mixed with food or fluid, or chewed Enteric coated pills can’t be crushed before administration Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

PRACTICE MD order: sucralfate 1 g p. o. q. i. d. a. c. and

PRACTICE MD order: sucralfate 1 g p. o. q. i. d. a. c. and at bedtime MD order: clarithromycin 500 mg p. o. q 12 h MD order: clonazepam 1. 5 mg p. o. t. i. d. Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Dosage Calculations: Ratio-Proportion Method • Three-step approach: 1. Convert 2. Think 3. Calculate Copyright

Dosage Calculations: Ratio-Proportion Method • Three-step approach: 1. Convert 2. Think 3. Calculate Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Three Steps to Dosage Calculations: Ratio-Proportion Method 1. Convert – All units of measurement

Three Steps to Dosage Calculations: Ratio-Proportion Method 1. Convert – All units of measurement must be in same system and all units must be in same size – If not, convert before proceeding 2. Think – Estimate reasonable amount of drug to administer 3. Calculate – Set up ratio between dosage on hand desired dosage Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Convert • If dosage is not in same size unit of measurement, convert to

Convert • If dosage is not in same size unit of measurement, convert to same system or same size units • Remember: Proportions compare like things. • The ratio must follow the same sequence. The numerators of each represent the weight of the dosage, and the denominators represent the amount. Keep the known on the left side and the unknown (X) on the right. Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Converting to Same System • Math tip – In most cases, more practical to

Converting to Same System • Math tip – In most cases, more practical to convert a larger unit to smaller unit • Usually eliminates decimal or fraction, keeping calculation in whole numbers Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Converting to Same System • Math tip – Example: • Keflex 0. 5 g

Converting to Same System • Math tip – Example: • Keflex 0. 5 g p. o. ordered, but Keflex 500 mg capsules on hand • Both are metric system, but have to be converted to same unit of measurement • Better to convert g to mg and proceed with calculation Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Example One • Order: Lopressor 100 mg p. o. daily • Available: Lopressor 50

Example One • Order: Lopressor 100 mg p. o. daily • Available: Lopressor 50 mg tablets • How many tablets are needed to deliver the ordered dose? Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Example One 1. Convert – No conversion necessary • Units are in same system

Example One 1. Convert – No conversion necessary • Units are in same system (metric) and same size (mg) 2. Think – Need 100 mg and have 50 mg per tablet – Want to give twice the equivalent of each tablet • Two tablets per dose Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Example One 3. Calculate Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Example One 3. Calculate Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Example One 3. Calculate Cross-multiply Simplify: Divide both sides by number before X Copyright

Example One 3. Calculate Cross-multiply Simplify: Divide both sides by number before X Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Example Two • Order: Flagyl 0. 75 g p. o. t. i. d. •

Example Two • Order: Flagyl 0. 75 g p. o. t. i. d. • Available: Flagyl 500 mg tablets • How many tablets per dose are needed? Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Step 1: Convert • Units are same system, but size is different • Equivalent:

Step 1: Convert • Units are same system, but size is different • Equivalent: 1 g = 1, 000 mg • Set up ratio: Cross-multiply Move decimal three places to right and add zeros: 0. 750. Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Step 2: Think • How many 500 mg tablets should be required to administer

Step 2: Think • How many 500 mg tablets should be required to administer 750 mg? Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Step 3: Calculate Cross-multiply Simplify Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Step 3: Calculate Cross-multiply Simplify Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Practice: Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Practice: Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Calculating Dosages for Oral Liquids • Use same three steps • Doses calculated in

Calculating Dosages for Oral Liquids • Use same three steps • Doses calculated in m. L • Example: – Order: Cefaclor 100 mg p. o. q. i. d. – Available: Cefaclor 125 mg per 5 m. L – Calculate one dose Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Step 1: Convert • No conversion necessary – Medication available in same unit as

Step 1: Convert • No conversion necessary – Medication available in same unit as order Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Step 2: Think • 100 mg ordered • 125 mg per 5 m. L

Step 2: Think • 100 mg ordered • 125 mg per 5 m. L available • Estimate giving less than 5 m. L Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Step 3: Calculate Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Step 3: Calculate Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Remember • Three steps to dosage calculation: 1. Convert to units of same system

Remember • Three steps to dosage calculation: 1. Convert to units of same system and size • Convert to smaller units – E. g. , g to mg • Convert household to metric system – E. g. , T to mg 2. Think • Estimate amount needed Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Remember • Three steps to dosage calculation: 3. Calculate Copyright © 2016 Cengage Learning.

Remember • Three steps to dosage calculation: 3. Calculate Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Remember • Consider reasonableness of calculated amount to give • Question giving more than

Remember • Consider reasonableness of calculated amount to give • Question giving more than three tablets or capsules per dose • CLARIFY as needed! Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Practice Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.

Practice Copyright © 2016 Cengage Learning. ALL RIGHTS RESERVED.