Order: Cloxacillin 100 mg PO q8h for a child who weighs 39 lb.

The recommended daily dosage is 20-40 mg/kg/day every 8 hours. Cloxacillin is available at 125 mg/5 mL.

a. Child's weight: 17.7 kg

b. Recommended minimum daily dosage:
\[20 \, \text{mg/kg/day} \times 17.7 \, \text{kg} = 354 \, \text{mg/day}\]

c. Recommended minimum single dosage:
\[354 \, \text{mg/day} \div 3 \, \text{doses/day} = 118 \, \text{mg/dose}\]

d. Recommended maximum daily dosage:
\[40 \, \text{mg/kg/day} \times 17.7 \, \text{kg} = 708 \, \text{mg/day}\]

e. Recommended maximum single dosage:
\[708 \, \text{mg/day} \div 3 \, \text{doses/day} = 236 \, \text{mg/dose}\]

f. Is the dosage ordered safe?
No, the order is for 100 mg; the range is 118-236 mg/dose.

g. If the dosage ordered is safe, calculate the dose:
No, the order is not safe due to underdosing.