Question

20. A physician orders 200mg of acyclovir IV for a patient with shingles. Acyclovir comes in a powdered form in a 0.5−g vial. The directions state it should be reconstituted with 5 mL of normal saline. How many mL would contain the ordered dosage?

Answer 1

2 mL of the reconstituted solution would contain the ordered dosage of 200 mg of acyclovir for the patient with shingles.

How to determine the quantity that would be contained the ordered dosage?

To determine how many mL would contain the ordered dosage, we can use the formula below to know the concentration of acyclovir.

`\[\text{Concentration of acyclovir} = \frac{\text{Amount of acyclovir}}{\text{Volume of solution}}\]`

Where;

Acyclovir amount = 0.5 g

Volume of solution = 5 mL

`\text{Concentration} = \frac{0.5 \text{ g}}{5 \text{ mL}} = 0.1 \text{ g/mL}`

Let us proceed to find the volume needed to contain the ordered dosage of 200 mg of acyclovir (which is 0.2 g):

We can use the formula:

`\text{Volume of solution} = \frac{\text{Dosage needed}}{\text{Concentration of solution}}`

Given:

Dosage needed = 200 mg = 0.2 g

Concentration of solution = 0.1 g/mL

Therefore,

`\text{Volume of solution} = \frac{0.2 \text{ g}}{0.1 \text{ g/mL}} = 2 \text{ mL}`

Hence, 2 mL of the reconstituted solution would contain the ordered dosage of 200 mg of acyclovir for the patient with shingles.