Sterile Compounding Calculations Flashcards

A physician orders 1,000 mL of D5W with 20 mEq of potassium chloride to infuse at 125 mL/hr. How long will the infusion take?

Answer: 8 hours

1,000 mL divided by 125 mL/hr equals 8 hours.

How many milligrams of vancomycin are in 200 mL of a 5 mg/mL solution?

Answer: 1,000 mg

5 mg/mL times 200 mL equals 1,000 mg.

A 70-kg patient requires dopamine at 5 mcg/kg/min. The concentration is 400 mg in 250 mL D5W. What is the infusion rate?

Answer: 13.1 mL/hr

Dose is 350 mcg/min. Concentration is 1,600 mcg/mL. Rate equals 350 divided by 1,600 times 60 equals 13.1 mL/hr.

What is the final concentration in percent (w/v) of 5 g of dextrose in 100 mL?

Answer: 5%

Percent w/v equals grams per 100 mL, so 5 g per 100 mL equals 5%.

Ampicillin 500 mg IV every 6 hours for 24 hours. How many total milligrams are needed?

Answer: 2,000 mg

24 hours divided by 6 hours equals 4 doses. 500 mg times 4 equals 2,000 mg.

Using alligation, how many mL of 70% dextrose and 5% dextrose are needed for 1,000 mL of 20% dextrose?

Answer: 231 mL of 70% and 769 mL of 5%

Using alligation: 15 parts of 70% and 50 parts of 5%. Total 65 parts. 70% needed: 15/65 times 1,000 equals 231 mL. 5% needed: 769 mL.