 # Drug Calculations Involving Reading Drug Labels, Part 1 – Nursing Math, Pharmacology*

In this dosage calculation problem it
states a patient is to receive 350 milligrams of Augmentin per dose.
Determine the proper amount of milliliters the patient is to receive.
Our goal will to have the answer in milliliters. The order is 350 milligrams
and that’s what we will start with. To convert from milligrams to milliliter we
consult the drug on hand and here is a screen shot of that drug and note
particularly the upper right hand corner which states that the ratio is 125
milligrams per 5 milliliters. We’ll use that relationship to convert
from the current order in milligram into milliliters. To set up our conversion
fraction we will want milligrams in the denominator so that it cancels out.
Placing these equivalent values 1 in the numerator and the denominator gives us a
fraction with a value of 1. Allowing us to convert the units will cancel out the
common milligram in the numerator and the denominators since they equal 1.
Perform the indicated multiplication of the fractions multiplying numerators and
multiplying denominators. Last step we will divide and note that our unit is in
milliliters so here we have the correct answer in milliliter per dose. In this
next problem it states Lavoxyl is prescribed to a hypothyroid patient, 12.5
micrograms per day. How many tablets should be given to this patient per day?
The question is asking tablets so we’ll set that as our goal. Beginning with the
doctor’s orders highlighted here and expressed as a fraction. We have 12.5
micrograms per day. Looking at this drug available on hand we have a label
showing here that there are 50 microgram in each tablet. We’ll use that
relationship then to convert from the current order in micrograms into tablets,
setting up our conversion fraction we’ll want to place the microgram value in the
denominator with the one tab in the numerator to give us our conversion
fraction with a value of 1. We now can cancel out the common factor of
micrograms in the numerator and the denominator since they have a value of 1.
Perform the multiplication of these fractions simplify the answer by
dividing numerator by denominator to give us a final answer of 0.25 tablets
per day or 1/4 tablet per day.