Fractional Ratio and Proportion in Nursing Dosage Calculations

What is a ratio?

A comparison of two numbers that are related to each other.

What is a proportion?

An equation of two equal ratios.

How can ratios be expressed?

In fractional format, using a horizontal line to separate the numbers.

What is the first step in solving a dosage calculation problem?

Write the known ratio.

What information is needed to calculate a dosage using proportions?

The dosage strength, the desired dose, and the unknown amount to be administered.

What does dosage strength include?

The strength of the medication with the unit of measurement and the number of capsules, tablets, or milliliters.

How is the dosage strength of Accupril expressed?

5 milligrams per tablet.

What is the dosage strength of Mesna?

1 gram per 10 milliliters.

What is the process to solve for 'x' in a proportion?

Cross multiply and then divide both sides by the number in front of x.

In the sample problem, how many tablets should the nurse administer for Medication M ordered at 10 milligrams?

2 tablets (since the dosage strength is 5 milligrams per tablet).

What is the correct answer for Practice Problem 1 involving 0.375 milligrams of Lanoxin?

3 tablets.

Why might conversions between units of measurement be necessary in dosage calculations?

Because the order may be in one unit while the pharmacy provides the drug in a different unit.

What do standard equivalent measurements help with in drug dosage calculations?

They provide necessary conversions between different measurement systems.

What is the dosage strength for the drug in Practice Problem 2?

500 milligrams per 10 milliliters.

How many teaspoons will the patient receive per dose for 500 milligrams of Griseofulvin?

4 teaspoons.

What should be checked after writing the known and unknown ratios?

Check the sequence of units to ensure they match.

What is the first action when solving a problem with different units?

Convert the units to match.

What is the significance of the unknown in dosage calculations?

It represents the amount of medication the nurse will administer.

What does cross multiplying help determine in ratio and proportion problems?

It helps find the value of the unknown variable 'x'.

What is the purpose of using fractional ratios in medication calculations?

To simplify the comparison of different dosages and strengths.