Pharmacy calculations worksheet with answers

A solution is 2% w/v. You need 64 mg of the drug. Draw up the volume in the syringe: what volume V is that?

Practice exercise (made-up values, not clinical guidance). Express the ratio strength 1:2 000 as a percentage strength p (% w/v).

A solution has a ratio strength of 1:10 000. You need 0.24 mg. Draw up the volume in the 10 mL syringe: what volume V is that?

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 8.2 mL of diluent. The prescribed dose is 1 200 000 units. What volume V do you draw up? Round to one decimal place.

A vial holds 500 mg of powder. You add 4.5 mL of diluent, and the powder adds 0.5 mL of volume. The prescription is 160 mg. Draw up the dose: what volume V do you give?

Practice exercise (made-up values, not clinical guidance). You must prepare 300 mL of 6% hydrogen peroxide from a 30% stock and purified water. How many mL V of water do you need? Round to the nearest whole mL.