Pharmacy calculations worksheet with answers

A solution is 0.5% w/v. You need 8 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 1:10 000. How many milligrams m are in 1000 mL?

Practice exercise (made-up values, not clinical guidance). A vial of penicillin G contains 5 000 000 units. Its practice label gives three strengths (see the table). You add 3.2 mL of diluent. The prescribed dose is 800 000 units. What volume V do you draw up? Round to one decimal place.

Practice exercise (made-up values, not clinical guidance). A vial contains ceftriaxone 2000 mg as a powder. The practice label says to add 19.2 mL of sterile water; the powder adds 0.8 mL to the volume. What is the concentration C in mg/mL after reconstitution?

A vial holds 500 mg of powder. You add 3.5 mL of diluent, and the powder adds 0.5 mL of volume. The prescription is 387.5 mg. Draw up the dose: what volume V do you give?

Practice exercise (made-up values, not clinical guidance). You must prepare 900 mL of 70% ethanol from a 90% stock and purified water. How many mL V of water do you need? Round to the nearest whole mL.