What volume of Kantrex 500 mg/mL should be administered for a 125 mg dose?

To determine the correct volume of Kantrex (which is equivalent to 500 mg/mL) that should be administered for a 125 mg dose, it's important to use the concentration of the medication to perform the calculation.

Given that the concentration of Kantrex is 500 mg/mL, this means that each mL contains 500 mg of the drug. To find out how much volume we need to calculate a 125 mg dose, we can use a simple formula:

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

Substituting in the values:

Volume (mL) = 125 mg / 500 mg/mL

When you do the calculation, it becomes:

Volume = 0.25 mL

Thus, the correct volume of Kantrex to administer for a 125 mg dose is 0.25 mL. This makes option B the correct choice, as it accurately reflects the required volume based on the provided concentration. Understanding how to manipulate these types of dosage calculations is key in pharmacology, as it ensures accurate and effective administration of medications.