Chapter 8 Flashcards
Calculating Oral Medication Doses
What is a dose?
The specific amount of medication to be administered at one time (e.g., 500 mg).
What is dosage?
The total amount of medication prescribed over a period, including size, frequency, and number of doses.
Why is accurate dosing important?
To prevent medication errors that can harm patients and ensure effective treatment.
Who is involved in ensuring correct medication dosing?
Physicians, pharmacists, and pharmacy technicians.
What is the Ratio and Proportion (R&P) method?
A mathematical method using cross-multiplication to find unknown quantities in dosing calculations.
How do you set up a proportion using R&P?
Compare the known dose to the stock strength, e.g., e.g. 250 mg / 1 tablet = 500 mg / x tablets
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What is Dimensional Analysis (DA)?
A method that uses conversion factors to ensure units cancel appropriately, making calculations clearer.
How do you use DA for medication calculations?
Start with the desired unit and use fractions to convert to the needed unit, e.g., 500 mg x (1 tablet / 250 mg) = 2 tablets
What are scored tablets?
Tablets that have a line down the middle and can be safely split into smaller doses.
What are unscored tablets?
Tablets that should not be divided as it can affect their effectiveness.
What are enteric-coated medications?
Medications designed to pass through the stomach without breaking down; they should not be crushed or chewed.
Why should capsules generally not be opened?
Opening capsules can alter how the medication is absorbed in the body.
What is the process for calculating solid oral medication doses?
Use R&P for single-step calculations and DA for multi-step problems involving different units.
What is a conversion factor?
A ratio used to convert between different units of measurement (e.g., 1 g = 1000 mg).
How do you round medication doses?
Round to the nearest whole number or decimal place as appropriate for safe administration.
Why is it important to double-check calculations?
To catch any mistakes before administering medication, ensuring patient safety.
What should you do if you have doubts about a medication calculation?
Consult a pharmacist for clarification before proceeding.
What is the significance of patient safety in medication dosing?
Accurate calculations and proper administration are essential to minimize risks and ensure effective treatment.
What are the key steps in the medication dispensing process?
Verify the medication order, check labels three times, and ensure the correct dosage form is used.
What is the role of healthcare professionals in medication safety?
They work collaboratively to ensure that medications are administered safely and effectively.
What are oral medications?
Medications taken by mouth. They come in solid and liquid forms.
What is a dose?
The amount of medicine to be given at one specific time.
What is dosage?
The size, frequency, and number of doses of medication prescribed over a period of time.
Why is it important to calculate medication doses accurately?
Accurate calculations are essential for patient safety.
What are scored tablets?
Tablets with an indentation that allows them to be split into even halves or thirds.
What are enteric-coated tablets?
Tablets designed to pass through the stomach unchanged. They should never be divided, crushed, or chewed.
What are extended-release and delayed-release formulations?
Formulations designed to release medication slowly over time. They should generally not be crushed, chewed, or divided.
What are buccal medications?
Medications placed between the gum and cheek.
What are sublingual medications?
Medications placed under the tongue.
Can capsules be crushed, chewed, or divided?
Most capsules should not be crushed, chewed, or divided. A few can be opened and sprinkled on food.
What are the two main methods for calculating medication doses?
Ratio and Proportion (R&P) and Dimensional Analysis (DA)
When is it best to use the Ratio and Proportion (R&P) method?
For single-step calculations.
How do you set up a ratio and proportion equation?
Write the relationships as fractional units. Place known dose and dosage form on the left, unknown on the right. Units in numerators and denominators must be the same.
What is the key rule to remember when using R&P?
Only cross-multiply and divide.
When is Dimensional Analysis (DA) particularly useful?
For calculations with more than one step and when converting between units.
How do you set up a dimensional analysis equation?
Start with the desired unit, then use fractions with known quantities and conversion factors to cancel out unwanted units.
What is the key rule to remember when using DA?
Multiply fractions. Never cross-multiply.
What are some important safety rules for calculating doses?
Recheck calculations.
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Ask the pharmacist if you have questions.
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Verify medication and dosage form.
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Check labels three times.
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Compare label to physician’s order.
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Be aware of look-alike and sound-alike medications.
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Know usual doses and check package insert if unsure.
What should you do if your answer doesn’t seem right?
Recalculate. If still unsure, ask the pharmacist. Never fill an order if you have a question.
Who is ultimately responsible for dispensing the correct medication?
The pharmacist.
What are the common units of measurement used for solid oral medications?
Milligrams (mg)
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Grams (g)
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Grains (gr)
What is a conversion factor?
A numerical relationship that allows you to convert between different units of measurement. For example, 1 gram (g) = 1000 milligrams (mg).
When is a conversion factor needed?
When the medication order and the available medication are in different units of measurement.
Which calculation method is best for multistep problems with conversions?
Dimensional Analysis (DA). It helps to keep track of units and make the entire conversion in one equation.
What is the conversion factor for grains to milligrams?
1 grain (gr) = 60 milligrams (mg). This may be indicated in the problem or you may need to know it.
A physician orders metformin 500 mg qam. Available stock is 500 mg tablets. How many tablets are needed for one dose?
Since the order and the stock strength are the same, only one tablet is needed.
A physician orders metformin 1 g qam. The available stock is 500 mg tablets. How many tablets are needed?
Step 1: Convert grams to milligrams: 1 g = 1000 mg
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Step 2: Set up the DA equation: tabs = (1 tab / 500 mg) * (1000 mg / 1 g) * 1 g = 2 tablets
A physician orders phenobarbital gr 1/4 tid. The available stock is phenobarbital 15 mg tablets. How many tablets are needed for one dose?
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Step 1: Convert grains to milligrams: gr 1 = 60 mg, so gr 1/4 = 15 mg
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Step 2: Since the dose and stock strength are the same, only one tablet is needed.
What happens if the calculated dose is not a whole number of tablets or capsules?
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Round to the nearest whole number if the tablets are not scored.
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Round to the nearest half-tablet if the tablets are scored.
What are some examples of combination products?
Lotrel 2.5/10, which contains 2.5 mg of amlodipine and 10 mg of benazepril in each tablet.
How should doses of combination products be ordered?
In equal multiples of each component. For example, Lotrel 5/20 is an acceptable dose because both components are doubled from the original strength.
Provide an example of a medication order that cannot be filled with Lotrel 2.5/10 tablets.
Lotrel 3/10. This dose cannot be achieved using the 2.5/10 tablets because the amlodipine component is not in a multiple of 2.5.
List five generic names of medications and their corresponding brand names from the sources.
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phenytoin (Dilantin)
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digoxin (Lanoxin)
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clarithromycin (Biaxin)
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pravastatin (Pravachol)
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lorazepam (Ativan)
List five more generic names of medications and their corresponding brand names from the sources.
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zidovudine (Retrovir)
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dexamethasone (Decadron)
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quinapril (Accupril)
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pregabalin (Lyrica)
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sumatriptan (Imitrex)
What is the difference between a dose and a dosage?
A dose is the amount given at one time, while dosage refers to the total amount prescribed over time, including frequency and duration.
What factors must be considered when calculating medication doses?
Patient age, weight, medical conditions, and the specific medication’s characteristics.
What is the significance of stock strength in medication calculations?
Stock strength indicates the concentration of the medication available, which is crucial for determining how much to dispense.
How do you calculate the number of tablets needed if the ordered dose is higher than the stock strength?
Use R&P or DA to determine how many tablets or capsules are required to meet the ordered dose.
What is the importance of checking for look-alike and sound-alike medications?
To prevent medication errors that could arise from confusion between similar drug names.
What should be done if a calculated dose involves a fraction of a tablet?
Ensure that the tablet can be safely divided (e.g., scored tablets) and that the calculation does not alter the medication’s effectiveness.
What are the common routes of administration for oral medications?
Tablets, capsules, solutions, and suspensions.
What is the role of the pharmacist in medication dispensing?
The pharmacist verifies the accuracy of medication orders, checks for potential drug interactions, and ensures patient safety.
What precautions should be taken when handling medications?
Maintain a distraction-free environment, double-check calculations, and follow safety protocols.
How should medications be stored to maintain their effectiveness?
Store at controlled room temperature, protect from light and moisture, and follow specific storage instructions on the label.
What is the significance of patient education regarding medication?
Educating patients about their medications helps ensure adherence, understanding of side effects, and proper usage.
