Compounding Calculations Flashcards

What volume of a 20% lipid emulsion provides 200 kcal? (Fat = 9 kcal/g; 20% = 20 g/100 mL)

Answer: 111 mL

20 g/100 mL × 9 kcal/g = 1.8 kcal/mL; 200 kcal ÷ 1.8 kcal/mL ≈ 111 mL.

A TPN order calls for 50 mEq of sodium bicarbonate. The stock vial is 8.4% (1 mEq/mL). How many mL are needed?

Answer: 50 mL

8.4% sodium bicarbonate = 1 mEq/mL; 50 mEq ÷ 1 mEq/mL = 50 mL.

You prepare 500 mL of a parenteral solution. The label requires a 1:200 concentration of drug. How many grams of drug are in the bag?

Answer: 2.5 g

1:200 = 1 g per 200 mL; for 500 mL: 500/200 = 2.5 g.

An order requires tobramycin 5 mg/kg/day divided every 8 hours for a 60 kg patient. What is the dose per administration?

Answer: 100 mg

Daily dose = 5 × 60 = 300 mg/day; divided q8h = 300 ÷ 3 = 100 mg per dose.

Which calculation correctly determines the flow rate (mL/hr) for a 1 g drug infused over 30 minutes in 100 mL NS?

Answer: 200 mL/hr

100 mL over 0.5 hr = 100 ÷ 0.5 = 200 mL/hr.

A stock solution contains 250 mg/5 mL. How many mL are needed to provide a 75 mg dose?

Answer: 1.5 mL

Concentration = 50 mg/mL; 75 mg ÷ 50 mg/mL = 1.5 mL.

A compounder adds 20 mEq of KCl and 30 mEq of NaCl to a 1 L TPN. The combined mEq of monovalent electrolytes is:

Answer: 50 mEq

Both KCl and NaCl contribute 1 mEq/mEq of monovalent ions; total = 20 + 30 = 50 mEq.