Complex / Doris Turner Med Math
Questions
1. Problem type: IV infusion rate + infusion
pump Medication: azithromycin
PROBLEM
Suppose Mrs. Turner’s
... [Show More] orders call for 500 mg of azithromycin to be administered
intravenously for communityacquired pneumonia. The solution has been diluted to a
concentration of 2 mg/mL and needs to be administered over 1 hour.
At what rate should the infusion pump be set?
HINT
Start by figuring out how many milliliters will be needed to administer the ordered dose.
SAMPLE SOLUTION
1. Determine how many milliliters of the concentration will be delivered to
administer the ordered dose.
500 mg x 1 mL = 250 mL
2 mg
2. Divide the total number of mL needed to deliver the 500 mg by the
expected duration of 1 hour.
250 mL = 250 mL/hr
1 hr
ANSWER
Number: 250
Units / Rate: mL/hr
2. Problem type: Dosage calculation + Stock on
hand Medication: venlafaxine
PROBLEM
Mrs. Turner’s daily medications include venlafaxine extendedrelease, 150 mg, by mouth,
once a day. However, the hospital pharmacy only carries 75 mg extendedrelease
tablets.
How many tablets of venlafaxine extendedrelease should be administered to her?
HINT
You can use the equation below, where X is the number of tablets that should be
administered.
D (ordered dose) x Quantity = X
H (dose on hand)
SAMPLE SOLUTION
1. Determine what information you have.
D (ordered dose) = 150 mg
H (dose on hand) = 75 mg
Q (quantity) = 1 tablet
2. Plug into the equation and solve.
D (150 mg) x 1 tablet = X
H (75 mg)
X = 2 tablets
ANSWER
Number: 2
Units: tablets
3. Problem type: Total daily dosage
Medication: Acetaminophen @ hospital hypothetical
Suppose Mrs. Turner’s provider updated her order for 325 mg, 2 tabs, by mouth q6h
PRN temp. > 100.5 F to 325 mg, 2 tabs, by mouth q4h PRN temp. > 100.5 F. The
Davis’s Drug Guide reports that acetaminophen has a maximum recommended dosage
of 4 g/day.
How many doses can Mrs. Turner take without exceeding the recommended maximum
dosage?
HINT
There are 1000 mg in one gram.
SAMPLE SOLUTION
1. Determine how many milligrams are in 4 grams.
4 g x 1000 mg = 4000 mg
1 g
2. Determine how many 325 mg tablets go into 4000
mg. 4000 mg x 1 tablet = 12.3 tablets
325 mg
3. Round down to the nearest whole tablet = 12 tablets
4. Divide the total number of tablets by the number tablets in a dose.
12 tablets total x 1 dose = 6 doses
2 tablets
ANSWER
Number: 6
Units: doses
4. Problem type: Total daily dose calculation
Medication: acetaminophen @ hospital
PROBLEM
Suppose Mrs. Turner’s current temperature is 100.8 F. For temperatures greater than 100.5
F, the prescriber’s order allows acetaminophen, 325 mg, 2 tabs, by mouth, every 6 hours.
Assume that on her first day of hospitalization, Mrs. Turner’s temperature is greater than
100.5 F three times.
How many grams of acetaminophen will she have ingested on her first day of
hospitalization? Round your answer to hundredths.
HINT
Multiply the number of taken doses by the number of tablets.
SAMPLE SOLUTION
1. Multiply the number of doses taken by the number of tablets per dose.
3 doses x 2 tablets = 6 tablets
1 dose
2. Multiply the dosage of acetaminophen by the number of tablets.
6 tablets x 325 mg = 1950 mg
1 tablet
3. Convert the total daily milligrams to grams.
1950 mg x 1 g = 1.95 g
1000 mg
ANSWER
Number: 1.95
Units: g
5. Problem type: Dosage calculation + Stock on
hand Medication: potassium chloride
PROBLEM
Mrs. Turner’s daily medications include potassium chloride, 10 mEq tablet by mouth
once daily. The hospital pharmacy will dispense potassium chloride liquid 10% (1.5
gram or 20 mEq per 15 mL). The KCl liquid will be further diluted in a 6 oz glass of water
or juice for administration.
What volume of the KCl 10% liquid should be used for Mrs. Turner’s usual daily dose?
HINT
Multiply the desired dose by the concentration.
SAMPLE SOLUTION
1. Multiply the desired dose by the concentration.
10 mEq x 15 mL = 7.5 mL of KCl 10% liquid
day 20 mEq day
ANSWER
Number: 7.5
Units: mL / day
6. Problem type: IV flow + allergic
reaction Medication: ceftriaxone
hypothetical
PROBLEM
Mrs. Turner’s original orders called for ceftriaxone, 1g, to be administered intravenously
daily. The solution has been diluted to a concentration of 1 g / 50 mL to be administered
over 30 minutes. Twenty minutes into the first infusion, Mrs. Turner reports an adverse
reaction to the antibiotic and the infusion is stopped.
How many mL of concentration were administered before the infusion was stopped?
Round your answer to the nearest whole number.
HINT
Divide the time elapsed by the infusion rate to determine the completion percentage of
the infusion.
SAMPLE SOLUTION
1. Determine the completion percentage of the infusion.
20 min (time elapsed) = 0.667 (or 66.7 %)
30 min (total infusion time)
2. Multiply the infusion volume by the percentage.
50 mL x 0.667 = X
X = 33 mL
ANSWER
Number: 33
Units: mL
7. Problem type: Dosage calculation + weightbased dosage
Medication: azithromycin @ hospital hypothetical
According to the Davis’s Drug Guide, children sixmonthsold or younger with communityacquired pneumonia can be administered azithromycin orally using a weightbased
dosage. Children in this age group can receive 10 mg/kg on the first day, then 5 mg/kg for
four more days. Assume you need to administer this to a child weighing
20.3 lbs.
What is the total dose of azithromycin the child will receive over five days? Round
your answer to the nearest whole number.
HINT
Convert pounds to kilograms, and multiply the weight by the dosage.
SAMPLE SOLUTION
1. Convert pounds (lbs) to kilograms (kg).
20.3 lbs x 1 kg = 9.227 kg
2.20 lb
2. Multiply the first day’s dosage by weight in kg.
10 mg x 9.227 kg = 92.27 mg
kg
3. Multiply the dosage given for days 25 by weight in kg, and multiply by the number of
days administered (4).
9.227 kg x 5 mg x 4 = 184.54 mg
kg
4. Add the results from steps 2 and 3.
92.27 mg + 184.54 mg = 276.81 mg, rounded to 277 mg
ANSWER
Number: 277 mg
Units: mg
8. Problem type: Unit conversation + stock on
hand Medication: levothyroxine @ hospital
Mrs. Turner’s orders called for 50 mcg of levothyroxine, by mouth, daily. The pharmacy
stocks the medication in 0.025 mg tablets.
How many tablets are needed to administer the ordered dose?
HINT
Start by converting 50 mcg to mg. Then use the equation below, where X is the number
of tablets that should be administered.
D (ordered dose) x Quantity = X
H (dose on hand)
SAMPLE SOLUTION
1. Convert micrograms (mcg) to milligrams (mg).
50 mcg x 1 mg = 0.05 mg
1000 mcg
2. Determine what information you have.
D = 0.05 mg
H = 0.025 mg
Q = 1 tablet
3. Plug into the equation and solve.
D (0.05 mg) x 1 tablet = X
H (0.025 mg)
X = 2 tablets
ANSWER
Number: 2 [Show Less]