PTCB Practice Test 11
Pharmacy Calculations Quiz
08:00
Question 1
A physician orders 60 mg of a medication. The medication is available in 40 mg/5 mL. How many milliliters should be administered?
Correct!
Calculation: (60 mg ÷ 40 mg) × 5 mL = 7.5 mL. You would administer 7.5 mL to give 60 mg of the medication.
Incorrect
The correct calculation is: (60 mg ÷ 40 mg) × 5 mL = 7.5 mL. You would administer 7.5 mL to give 60 mg of the medication.
Question 2
A prescription calls for 0.25 g of a drug. The drug is available in 125 mg tablets. How many tablets should be dispensed?
Correct!
First convert 0.25 g to mg (0.25 g × 1000 = 250 mg). Then divide by tablet strength: 250 mg ÷ 125 mg/tablet = 2 tablets.
Incorrect
The correct calculation is: 0.25 g = 250 mg. Then 250 mg ÷ 125 mg/tablet = 2 tablets. Always ensure units match before calculating.
Question 3
A patient needs 500 mg of amoxicillin. The available suspension is 250 mg/5 mL. How many teaspoons should the patient take? (1 tsp = 5 mL)
Correct!
(500 mg ÷ 250 mg) × 5 mL = 10 mL needed. Since 1 teaspoon = 5 mL, the patient should take 2 teaspoons.
Incorrect
First calculate mL needed: (500 mg ÷ 250 mg) × 5 mL = 10 mL. Then convert to teaspoons (5 mL per teaspoon): 10 mL ÷ 5 mL/tsp = 2 teaspoons.
Question 4
How many 30 mg codeine tablets are needed to compound 180 mL of a liquid containing 1 mg of codeine per mL?
Correct!
Total codeine needed: 180 mL × 1 mg/mL = 180 mg. Number of tablets: 180 mg ÷ 30 mg/tablet = 6 tablets.
Incorrect
First calculate total mg needed (180 mL × 1 mg/mL = 180 mg), then divide by tablet strength (180 mg ÷ 30 mg/tablet = 6 tablets).
Question 5
A physician orders 1.5 g of a medication to be added to 500 mL of IV fluid. The medication is available as 500 mg/2 mL. How many mL should be added to the IV bag?
Correct!
First convert 1.5 g to mg (1.5 g × 1000 = 1500 mg). Then calculate: (1500 mg ÷ 500 mg) × 2 mL = 6 mL.
Incorrect
Convert grams to milligrams first (1.5 g = 1500 mg). Then: (1500 mg ÷ 500 mg) × 2 mL = 6 mL should be added to the IV bag.
Question 6
A patient is prescribed 0.125 mg of digoxin daily. The available tablets are 62.5 mcg each. How many tablets should the patient take daily?
Correct!
First convert 0.125 mg to mcg (0.125 mg × 1000 = 125 mcg). Then divide by tablet strength: 125 mcg ÷ 62.5 mcg/tablet = 2 tablets.
Incorrect
Convert mg to mcg first (0.125 mg = 125 mcg). Then calculate: 125 mcg ÷ 62.5 mcg/tablet = 2 tablets daily.
Question 7
A pediatric dose of amoxicillin is 20 mg/kg/day divided every 8 hours. For a 22 lb child, what is the appropriate dose per administration?
Correct!
First convert weight: 22 lb ÷ 2.2 = 10 kg. Daily dose: 20 mg/kg × 10 kg = 200 mg/day. Divided every 8 hours (3 doses): 200 mg ÷ 3 ≈ 66.7 mg per dose.
Incorrect
Convert weight to kg (22 lb ÷ 2.2 = 10 kg). Calculate daily dose (20 mg/kg × 10 kg = 200 mg/day). Divide by 3 doses per day: 200 mg ÷ 3 ≈ 66.7 mg per dose.
Question 8
How many grams of dextrose are in 500 mL of D5W (5% dextrose in water)?
Correct!
5% means 5 g per 100 mL. For 500 mL: (5 g ÷ 100 mL) × 500 mL = 25 g of dextrose.
Incorrect
Percentage solutions are grams per 100 mL. 5% = 5 g/100 mL. For 500 mL: (5 g ÷ 100 mL) × 500 mL = 25 g of dextrose.
Question 9
A prescription requires 30 mg of a drug per dose. The drug is available as a 1:100 solution. How many mL should be administered per dose?
Correct!
1:100 means 1 g in 100 mL = 10 mg/mL. For 30 mg: 30 mg ÷ 10 mg/mL = 3 mL.
Incorrect
1:100 solution means 1 g in 100 mL = 10 mg/mL. To get 30 mg, you would need 30 mg ÷ 10 mg/mL = 3 mL.
Question 10
A patient is to receive 750 mg of a drug daily in 3 divided doses. The drug is available as 250 mg capsules. How many capsules should the patient take per dose?
Correct!
Daily dose is 750 mg ÷ 3 doses = 250 mg per dose. Since capsules are 250 mg each, the patient should take 1 capsule per dose.
Incorrect
The correct calculation is: 750 mg daily ÷ 3 doses = 250 mg per dose. Since capsules are 250 mg each, the patient should take 1 capsule per dose.
Your Score: 8/10 (80%)
Congratulations! You passed the quiz.
