Question

The recommended dosage of Rocephin is 50 to 100 mg/kg/day divided into two equal doses. The physician has ordered Rocephin 200 mg IM b.i.d. for a child who weighs 5000 g. The Rocephin vial contains 1 g of medication that must be reconstituted with 3.6 mL of diluent to yield 1 g/4 mL. Compute the recommended minimum and maximum amount of milligrams that the child should receive per day.

___ minimum, ____ maximum

Answer 1

Recommeded dosage =  50 to 100 mg/kg/day

Weight of child = 5000gm

Since, 1kg = 1000gm, weight of child = 5kg (1kg/1000g x 5000g)

Therefore, minimun dosage for the child = 50mg/kg/day x 5kg = 250mg/day

Maximum dosage for the child = 100mg/kg/day x 5kg = 500mg/day

Now, 1g = 1000mg

Therefore 500mg = 1g/1000mg x 500mg = 0.5gm and 250mg = 1g/1000mg x 250mg = 0.25gm

Provided that the vial contains 1 g/4 mL we get 0.25g/1mL (Normal division) and 0.5g/2mL (Multipying the numerator and denominator by 2)

Hence, the child will recieve from 1mL (min) to 2mL(max) of medication per day.