If the pediatric dosage of chlorothiazide (diuril) is 10 to 20
mg/kg of body weight per day in a single dose or two divided doses,
not to exceed 375 mg/day, calculate the daily dosage range of an
oral suspension containing 250 mg chlorothiazide per 5 ml that
should be administered to a 48-lb child.

The daily dosage range of an oral suspension containing 250mg of chlorothiazide per 5mL that should be administered to a 48lb child is 4.35 to 7.5mL.

Explanation:

The first thing to do is to convert the child's weight's units from pounds to kilograms: 48lb*(0.4536kg/lb) = 21.77kgThen we calculate the lower and upper limits of chlorothiazide for this child: 10mg/kg*21.77kg = 217.7mg, and 20mg/kg*21.77kg = 435.46mg. We have to remember that he can't take more than 375mg/day.The oral suspension's concentration is: 250mg/5mL. To calculate the daily dosage range of the suspension for this child, we use two "rules of three"x(min) = (217.7mg*5mL)/(250mg) = 4.35mLx(max) = (375mg*5mL)/250mg) = 7.5mL