1.Easy
A solution is 0.5% w/v. You need 15.5 mg of the drug. Draw up the volume in the syringe: what volume V is that?
0.5% w/v15.5 mg
V = mL
Pharmacy calculations worksheet with answers
2.Easy
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?
1:10 0001000 mL
m = mg
3.Medium
A solution has a ratio strength of 1:1000. You need 0.11 mg. Draw up the volume in the 1 mL syringe: what volume V is that?
1:10000.11 mg
V = mL
4.Medium
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?
2000 mg19.2 mL+0.8 mL
C = mg/mL
5.Hard
A vial holds 2000 mg of powder. You add 9.8 mL of diluent, and the powder adds 0.2 mL of volume. The prescription is 360 mg. Draw up the dose: what volume V do you give?
2000 mg9.8 mL + 0.2 mL360 mg
V = mL
6.Hard
A vial holds 2000 mg of powder. You add 9.2 mL of diluent, and the powder adds 0.8 mL of volume. The prescription is 220 mg. Draw up the dose: what volume V do you give?
2000 mg9.2 mL + 0.8 mL220 mg
V = mL
Answer key
- 1. V = 3.1 mL
- 2. m = 100 mg
- 3. V = 0.11 mL
- 4. C = 100 mg/mL
- 5. V = 1.8 mL
- 6. V = 1.1 mL
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