Pharmacy calculations worksheet with answers

A solution is 0.5% w/v. You need 7.5 mg of the drug. Draw up the volume in the syringe: what volume V is that?

Practice exercise (made-up values, not clinical guidance). A solution of potassium permanganate has a ratio strength of 1:5 000. How many milligrams m are in 100 mL?

Practice exercise (made-up values, not clinical guidance). A vial contains ampicillin 1000 mg as a powder. The practice label says to add 3.5 mL of sterile water; the powder adds 0.5 mL to the volume. The prescribed dose is 600 mg. What volume V do you draw up? Round to one decimal place.

Practice exercise (made-up values, not clinical guidance). A vial contains ceftriaxone 1000 mg as a powder. The practice label says to add 9.6 mL of sterile water; the powder adds 0.4 mL to the volume. What is the concentration C in mg/mL after reconstitution?

Practice exercise (made-up values, not clinical guidance). You must prepare 100 mL of 5% chlorhexidine from a 20% stock and purified water. How many mL V of water do you need? Round to the nearest whole mL.

A vial holds 2000 mg of powder. You add 4.4 mL of diluent, and the powder adds 0.6 mL of volume. The prescription is 1640 mg. Draw up the dose: what volume V do you give?