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Chapter 13

Oral Dosages

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Objectives

Converting all measures within the problem to equivalent measures in one system of measurement

Using a proportion to solve problems of oral dosage involving tablets, capsules, or liquid medications

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Objectives (cont’d)

Using a proportion to solve problems of oral dosages of medications measured in milliequivalents

Using the stated formula as an alternative method of solving oral drug dosage problems

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Oral Dosages

Tablets Capsules Liquids

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Converting Measures

Example:

A physician ordered amoxicillin 0.5 g po four times a day. The drug is supplied in 500-mg capsules.

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Calculating Math

Dimensional Analysis

caps = 1 500mg 1g

0.5g 1000mg

500 1 caps

500

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Calculating Math

Proportion

0.5g : x :: 500mg : 1 (Change either mg or g)

500mg : x :: 500mg : 1

X= 1 caps

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Calculating Math

Formula

D Q x (Dose to be administered)

A

0.5g 1 500mg 1 1 caps

500mg 500mg

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Using Proportions to Solve Tablet and Capsule Medication Problems

FIGURE 13-1 Forms of solid oral medication. (Top row: Uniquely shaped tablet,capsule, scored tablet. Bottom row: Gelatin-coated liquid, extended-release capsule,and enteric-coated tablet. (From Potter PA, Perry AG: Fundamentals of nursing, ed 7,St Louis, 2009, Mosby.)

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Using Proportions to Solve Tablet and Capsule Medication Problems (cont’d)

Example:

The physician orders minocycline 200 mg po daily. Minocycline 50 mg is available. How many capsules will the nurse administer?

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Using Proportions to Solve Liquid Medication Problems

FIGURE 13-6 Plastic oral syringe. (From Clayton BD, Stock YN, Cooper S: Basic pharmacology for nurses, ed 15, St Louis, 2010. Courtesy Chuck Dresner.)

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Using Proportions to Solve Liquid Medication Problems (cont’d)

Example:

The physician ordered atovaquone 750 mg twice daily pc. Atovaquone is available 150 mg/mL. How many milliliters will the nurse administer?

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Using Proportions to Solve Problems Involving Milliequivalents

Example:The physician ordered Slow-K 20 mEq four times

a day with meals. The drug is available 10 mEq/5 mL. How many milliliters will the nurse administer?

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Alternative Formula Method: Capsules and Tablets

Oral dosages involving capsules and tablets Example:

The physician orders aspirin gr v po four times a day. Aspirin tablets gr ii are available. How many tablets will the nurse administer?

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Alternative Formula Method: Liquids

Oral dosages involving liquids Example:

The physician orders phenobarbital gr ii po twice a day. Phenobarbital elixir 10 mg/5 mL is available. How many milliliters will the nurse administer?