PTCE Dosage Calculations 3

Question 1

An IV is infusing at 50 mL/hr using a 15 gtt/mL drip set. What is the drop rate in gtt/min?

Accepted Answer

12.5 gtt/min

Answer

50 mL/hr × 15 gtt/mL ÷ 60 min/hr = 12.5 gtt/min.

Question 2

A topical cream is prescribed as 'apply TID to affected area, 30g tube.' At an estimated 1g per application, how many days will the tube last?

Accepted Answer

10 days

Answer

TID = 3 times daily; 30g ÷ 3g/day = 10 days.

Question 3

Convert 0.125 mg to micrograms (mcg).

Accepted Answer

125 mcg

Answer

1 mg = 1,000 mcg; 0.125 × 1,000 = 125 mcg.

Question 4

A patient needs a 2% lidocaine solution. How many mg of lidocaine are in 10 mL?

Accepted Answer

200 mg

Answer

2% = 2 g/100 mL = 20 mg/mL; 20 mg/mL × 10 mL = 200 mg.

Question 5

A physician orders phenobarbital 3 mg/kg for a child weighing 44 lbs. Tablets are 15 mg. How many tablets are needed?

Accepted Answer

6 tablets

Answer

44 ÷ 2.2 = 20 kg; 20 × 3 mg = 60 mg; 60 ÷ 15 mg/tab = 4 tablets.

(PTCE) Pharmacy Technician Certification Exam Practice Test