How many mL of codeine oral solution should a nurse administer for a desired dose of 20 mg, given that the concentration is 10 mg per 5 mL?

To determine the volume of codeine oral solution that should be administered to achieve a desired dose of 20 mg, you need to use the concentration of the solution. The concentration provided is 10 mg per 5 mL.

First, establish how much codeine is found in 1 mL of the solution. Since there are 10 mg in 5 mL, you can find the concentration per mL by dividing:

10 mg / 5 mL = 2 mg/mL

Now, to find out how many mL are needed to administer a total of 20 mg, you can use this concentration:

Desired dose (20 mg) / concentration (2 mg/mL) = 10 mL

Thus, to deliver 20 mg of codeine, you need to administer 10 mL of the oral solution, making this the correct volume for the order.