If a patient needs 7.5 mg, how many milliliters is that?

If a patient needs 7.5 mg, how many milliliters is that?

• A. 0.25 mL
• B. 0.5 mL
• C. 1 mL
• D. 2 mL

Answer: (B)

To convert a dose in milligrams to a volume in milliliters, you need the solution’s concentration (how many milligrams are in each milliliter). Use Volume (mL) = Dose (mg) ÷ Concentration (mg/mL). If the medication is 15 mg per mL, then 7.5 mg ÷ 15 mg/mL = 0.5 mL. So the dose of 7.5 mg corresponds to 0.5 mL with this concentration. Always check the label for the exact concentration, because a different concentration changes the required volume (for example, 7.5 mg at 10 mg/mL would be 0.75 mL; at 5 mg/mL it would be 1.5 mL).

To convert a dose in milligrams to a volume in milliliters, you need the solution’s concentration (how many milligrams are in each milliliter). Use Volume (mL) = Dose (mg) ÷ Concentration (mg/mL).

If the medication is 15 mg per mL, then 7.5 mg ÷ 15 mg/mL = 0.5 mL. So the dose of 7.5 mg corresponds to 0.5 mL with this concentration. Always check the label for the exact concentration, because a different concentration changes the required volume (for example, 7.5 mg at 10 mg/mL would be 0.75 mL; at 5 mg/mL it would be 1.5 mL).