A child with a seizure disorder receives a prescription for phenytoin 20 mg by mouth (PO) every 8 hours. The suspension is available in 125 mg/5 mL. How many mL should the nurse administer? (Enter the numerical value only. If rounding is required, round to the nearest tenth.)

Given: Ordered dose of phenytoin: 20 mg Concentration of phenytoin suspension: 125 mg/5 mL Step 1: Set up the proportion: Desired dose (mg) / Volume to administer (mL) = Concentration (mg/mL) Step 2: Substitute the values: 20 mg / Volume = 125 mg/5 mL Step 3: Solve for the unknown volume: Volume = 20 mg / (125 mg/5 mL) Volume = 20 mg x (5 mL / 125 mg) Volume = 0.8 mL