A prescription requires Erythromycin 150 mg every six hours for ten days. How much Erythromycin is needed for one dose if you have Erythromycin 250 mg/5 mL?

To determine the amount of Erythromycin needed for one dose, we first need to know how much Erythromycin corresponds to the prescribed 150 mg. The concentration of the Erythromycin solution is 250 mg per 5 mL.

We start by calculating how many milligrams are present in 1 mL of the solution:

250 mg/5 mL = 50 mg/mL.

Next, we can find out how much volume is needed to obtain the required 150 mg dose. To do this, we use the formula:

Volume needed (mL) = Desired dose (mg) / Concentration (mg/mL).

Substituting the values we have:

Volume needed = 150 mg / 50 mg/mL = 3.0 mL.

Thus, 3.0 mL of the Erythromycin solution is required to deliver the 150 mg dose. This aligns with the correct answer choice, which indicates that the calculated volume is sufficient for the prescribed dosage.