1.Easy
Practice exercise (made-up values, not clinical guidance). A solution of epinephrine has a ratio strength of 1:1 000. How many milligrams m are in 0.3 mL?
1:1 0000.3 mL
m = mg
Pharmacy calculations worksheet with answers
2.Easy
A solution is 5% w/v. You need 125 mg of the drug. Draw up the volume in the syringe: what volume V is that?
5% w/v125 mg
V = mL
3.Medium
A solution has a ratio strength of 1:1000. You need 0.3 mg. Draw up the volume in the 1 mL syringe: what volume V is that?
1:10000.3 mg
V = mL
4.Medium
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 18.2 mL of diluent. The prescribed dose is 2 400 000 units. What volume V do you draw up? Round to one decimal place.
18.2 mL → 250 000 units/mL2 400 000 units
V = mL
5.Hard
A vial holds 500 mg of powder. You add 2 mL of diluent, and the powder adds 0.5 mL of volume. The prescription is 180 mg. Draw up the dose: what volume V do you give?
500 mg2 mL + 0.5 mL180 mg
V = mL
6.Hard
A vial holds 1000 mg of powder. You add 9.4 mL of diluent, and the powder adds 0.6 mL of volume. The prescription is 360 mg. Draw up the dose: what volume V do you give?
1000 mg9.4 mL + 0.6 mL360 mg
V = mL
Answer key
- 1. m = 0.3 mg
- 2. V = 2.5 mL
- 3. V = 0.3 mL
- 4. V = 9.6 mL
- 5. V = 0.9 mL
- 6. V = 3.6 mL
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