A nurse is preparing to administer phenytoin 5 mg/kg/day PO divided in equal doses every 12 hr to a school-age child who weighs 38 lb. Available is phenytoin 50 mg chewable tablets. How many tablets should the nurse administer per dose? (Round the answer to the nearest whole number. Us a leading zero if it applies. Do not use a trailing zero.)

To calculate the dosage of phenytoin for the child, first convert the child's weight from pounds to kilograms, knowing that 1 kilogram equals 2.2 pounds. The child weighs 38 lb, which is approximately 17.27 kg (38 lb / 2.2). Next, multiply the child's weight in kilograms by the dosage prescribed: 5 mg/kg/day. For this child, that would be 86.36 mg/day (17.27 kg * 5 mg/kg). Since the dose is divided every 12 hours, the amount per dose would be 43.18 mg (86.36 mg/day divided by 2). With phenytoin 50 mg chewable tablets available, the nurse would administer one tablet per dose.