PEBC Pharmaceutical Calculations 3

Question 1

A TPN bag contains 500 mL of 50% dextrose. How many grams of dextrose and how many kilocalories does this provide? (1 g dextrose = 3.4 kcal)

Accepted Answer

250 g, 850 kcal

Answer

250 g, 1000 kcal

Answer

125 g, 425 kcal

Answer

500 g, 1700 kcal

Question 2

A physician orders 40 mEq of KCl IV over 4 hours. KCl is available as 2 mEq/mL. How many mL of KCl should be added to the IV bag?

Accepted Answer

20 mL

Answer

10 mL

Answer

40 mL

Answer

80 mL

Question 3

What is the osmolarity of a 0.9% NaCl (normal saline) solution? (NaCl MW = 58.5 g/mol; assume complete dissociation into Na⁺ and Cl⁻)

Accepted Answer

308 mOsm/L

Answer

154 mOsm/L

Answer

277 mOsm/L

Answer

513 mOsm/L

Question 4

Vancomycin 1500 mg is to be infused over 1.5 hours using a concentration of 5 mg/mL. What volume and rate should be set?

Accepted Answer

300 mL at 200 mL/hr

Answer

500 mL at 333 mL/hr

Answer

150 mL at 100 mL/hr

Answer

200 mL at 133 mL/hr

Question 5

Using Young's rule [Child dose = Age/(Age + 12) × Adult dose], what is the dose for an 8-year-old child when the adult dose is 500 mg?

Accepted Answer

200 mg

Answer

167 mg

Answer

250 mg

Answer

133 mg

Question 6

Which ratio strength is equivalent to a 0.02% (w/v) solution?

Accepted Answer

1:5000

Answer

1:200

Answer

1:500

Answer

1:2000

Question 7

A drug has an elimination half-life of 6 hours. If a patient receives a 400 mg dose, how much drug remains after 18 hours?

Accepted Answer

50 mg

Answer

25 mg

Answer

100 mg

Answer

200 mg