PTCB Order Entry 2/6

The prescribed dose of Humulin R U-100 insulin is 10 units q.a.m. and 30 units q.p.m. a.c.

How many 10 mL vials will be needed for a minimum of 30 days supply?

• 1

• 2

• 3

• 4

Answer explanation

In order to solve this problem, you need to understand that U-100 insulin means that there are 100 units of insulin in 1 mL. You also need to understand abbreviations: “q.a.m.” means in the morning, “q.p.m.” means in the evening, and “a.c.” means before meals. The patient is taking 10 units of insulin in the morning before a meal and 30 units of insulin in the evening before a meal, so they are taking 40 total units per day (10 units + 30 units = 40 units). Since the problem asks how many vials you need for a 30-day supply, you first need to determine how many units the patient needs for 30 days. This can be done using multiplication (40 units/day × 30 days = 1200 units). Finally, since 10 mL vials are available, you need to calculate how many to dispense. There are 100 units of insulin in 1 mL, so in 10 mL there are 1000 units of insulin (100 units/mL × 10 mL/vial = 1000 units/vial). If 1200 units are needed for 30 days, determine how many vials are needed using division.

1200 units ÷ 1000 units/vial = 1.2 vials (round up to 2 vials because if you only dispensed one you would not provide enough for 30 days)

According to USP Chapter 795, what would be the latest possible beyond use date for a nonaqueous medication compounded on June 2, 2025?

• July 2, 2025

• September 2, 2025

• December 2, 2025

• June 2, 2026

Answer explanation

According to the United States Pharmacopeia (USP) Chapter 795, the beyond-use date for nonaqueous formulations is not later than the time remaining until the earliest expiration date of any ingredient, or 6 months, whichever is earlier. June 2, 2025, plus six months equals December 2, 2025, so that is the latest possible beyond-use date for this medication.

Which of the following should be used to identify a particular batch of compounded product?

• Lot number

• Expiration date

• Prescriber name

• Pharmacy name

Answer explanation

• Food and Drug Administration (FDA) defines lot numbers, control numbers, and batch numbers as any distinctive combination of letters, numbers, or symbols, or any combination of thereof, from which the complete history of the manufacture, processing, packing, holding, and distribution of a batch or lot of drug product or other material can be determined.

The recommended starting dose of a chemotherapy agent is 20 mg/kg, calculated to the nearest whole tablet. It is available in 250 mg tablets.

A patient weighing 162 lbs should receive a starting dose of how many tablets?

• 6

• 13

• 29

• 30

Answer explanation

The first step in solving this problem is to calculate how many mg the patient needs for their starting dose of chemotherapy. You have the dose available to you in mg/kg, but the patient weight is in lbs, so lbs needs to be converted to kg. There are 2.2 lb in 1 kg, so 162 lb ÷ 2.2 lb/kg = 73.6 kg.

Next, you can calculate how many mg the patient needs for their starting dose using the dose given to you.

20 mg/kg × 73.6 kg = 1472 mg

The final step is to calculate how many tablets the patient will need for the starting dose, and 250 mg tablets are available. This will be done by division.

1472 mg ÷ 250 mg/tablet = 5.9 tablets, and this should be rounded to the nearest whole tablet, which is 6 tablets.

A chemotherapy regimen calls for cisplatin 75 mg/m2. The patient's weight is listed at 80 kg, and his body surface area (BSA) is 1.8 square meters.

What is the proper dosage of cisplatin, in mg?

• 41.7

• 135

• 243

• 600

Answer explanation

To calculate the correct dose of cisplatin, you need to take the dosage and multiply it by the patient's BSA. The patient weight is listed as a Option and does not have anything to do with this problem.

75 mg/m2 × 1.8 m2 = 135 mg

A prescription reads:

Zithromax 200 mg/5 mL q.s. 1.5 tsp on day 1, then 3/4 tsp on days 2-5.

What volume, in mL, of Zithromax 200 mg/5 mL is needed for the entire course of therapy?

• 11.5

• 15

• 22.5

• 30

Answer explanation

The first step to answer this question is to understand the abbreviations and conversions. In this case, one "tsp" means one teaspoon, which is 5 mL. You must then calculate how much Zithromax (in mL) is required for each day. This conversion can be completed as follows:

Day 1: 1.5 tsp x 5 mL/1 tsp = 7.5 mL
Days 2-5: 3/4 tsp x 5 mL/1 tsp = 3.75 mL

By taking 7.5 and adding 4 x 3.75 mL (because the 3.75 mL dose is given for 4 days), you get a total of 22.5 mL as the entire course of therapy.

A physician orders amoxicillin 50 mg/mL for a child at 1 mL PO q8h for 10 days.

What is the total volume that must be dispensed, in mL, if the amoxicillin stock is 125 mg/5 mL?

• 2

• 30

• 60

• 150

Answer explanation

First, find how many mg the child should receive per day according to the instructions. Taking 1 mL of 50 mg/mL amoxicillin q8h means that the child will be taking 50 mg every 8 hours, or three times a day:

50 mg per dose x 3 doses per day = 150 mg per day

Since the stock amoxicillin contains 125 mg per 5 mL, this means that the stock contains 25 mg per mL. Divide 150 mg per day by 25 mg/mL to find how many mL are required per day:

150 mg per day ÷ 25 mg/mL = 6 mL per day

Finally, multiply the total mL required per day by the total days of therapy to find how many mL are needed to complete the course:

6 mL per day x 10 days of therapy = 60 mL total

The primary purpose of rotating inventory in the pharmacy is to:

• reduce the potential for dispensing expired medications.

• check for drug recalls.

• help determine what needs to be placed on the next inventory order.

• provide work for students and interns in the pharmacy.

Answer explanation

Stock rotation entails placing medications that have earlier expiration dates in front of medications that have later expiration dates. This helps reduce the potential for dispensing expired medications because products are more likely to be used up prior to expiring.

If a pharmacy technician has drawn 50 units of U-100 insulin into a syringe, the plunger has been drawn to:

• 0.05 mL

• 0.5 mL

• 5 mL

• 50 mL

Answer explanation

The first step to answer this question is to understand the meaning of U-100 insulin, which is that 100 units of insulin are contained in 1 mL. Using this conversion figure, we can determine the number of mL required for 50 units of insulin by setting up a proportion and solving for x.

(100 units/mL) = (50 units/x mL) x = 0.5 mL

Indomethacin liquid must be compounded according to the following prescription: Indomethacin 2 mg/mL Cherry syrup q.s. ad 100 mL Sig: 5 mL PO b.i.d. Only 50 mg capsules of indomethacin are available.

How many capsules should be used to prepare this prescription?

• 4

• 6

• 8

• 10

Answer explanation

There is some extra information provided to you in this problem that you do not need in order to solve the problem: the directions of 5 mL PO b.i.d. The problem is asking you to calculate how much drug is needed for the compound, and the instructions for use have nothing to do with that. In order to solve the problem, you first need to determine the total quantity to be made with the compound. The abbreviation “ad” means up to, so to make this compound you will add enough cherry syrup up to 100 mL, making 100 mL the total quantity of the prescription. Next, you need to determine how much indomethacin is needed for the 100 mL, and this can be determined using the concentration of the compound, which is 2 mg/mL.

(2 mg/mL)(100 mL) = 200 mg

Next, since you have 50 mg indomethacin capsules available to you, you need to determine how many capsules it would take to give you 200 mg of indomethacin. This can be done using division.

200 mg ÷ 50 mg/capsule = 4 capsules