A nurse is preparing to administer cetirizine 5 mg PO. Available is cetirizine 2.5 mg/5 mL. How many mL should the nurse administer? (Round the answer to the nearest whole number. Use a leading zero if it applies. Do not use a trailing zero.)

Calculation: Desired dose = 5 mg. Available concentration = 2.5 mg/5 mL. Calculate the volume in milliliters (mL) to administer. Volume (mL) = Desired dose (mg) / (Available concentration (mg) / Available volume (mL)) = 5 mg / (2.5 mg / 5 mL) = 5 mg / 0.5 mg/mL = 10 mL.