1.Easy
Practice exercise (made-up values, not clinical guidance). How many mg of bupivacaine are in 20 mL of 0.25% w/v solution? Find m.
0.25% w/v20 mL
m = mg
Pharmacy calculations worksheet with answers
2.Easy
A solution is 5% w/v. You need 185 mg of the drug. Draw up the volume in the syringe: what volume V is that?
5% w/v185 mg
V = mL
3.Medium
A solution has a ratio strength of 1:1000. You need 0.87 mg. Draw up the volume in the 1 mL syringe: what volume V is that?
1:10000.87 mg
V = mL
4.Medium
A solution has a ratio strength of 1:1000. You need 0.13 mg. Draw up the volume in the 1 mL syringe: what volume V is that?
1:10000.13 mg
V = mL
5.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 120 mg. Draw up the dose: what volume V do you give?
1000 mg9.4 mL + 0.6 mL120 mg
V = mL
6.Hard
Practice exercise (made-up values, not clinical guidance). You must prepare 200 mL of 4% chlorhexidine from a 20% stock and purified water. How many mL V of water do you need? Round to the nearest whole mL.
20%0%4%200 mL
V = mL
Answer key
- 1. m = 50 mg
- 2. V = 3.7 mL
- 3. V = 0.87 mL
- 4. V = 0.13 mL
- 5. V = 1.2 mL
- 6. V = 160 mL
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