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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?