Pharmacy calculations worksheet with answers

A solution is 5% w/v. You need 140 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 1:2 500 as a percentage strength p (% w/v).

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). 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 2 400 000 units. What volume V do you draw up? Round to one decimal place.

Practice exercise (made-up values, not clinical guidance). You must prepare 600 mL of 5% sodium chloride by mixing 23% and 3% sodium chloride. How many mL V of the 23% solution do you need? Round to the nearest whole mL.

A vial holds 500 mg of powder. You add 3.6 mL of diluent, and the powder adds 0.4 mL of volume. The prescription is 450 mg. Draw up the dose: what volume V do you give?