Question

1. Ibuprofen 10 mg/kg every 6 hours is prescribed for a 6 month old infant with fever. The infant weighs 8 kg. Your bottle of ibuprofen is labeled 100 mg / 5 mL. How many mL will you give the infant for each dose?

2. Cephalexin 25 mg/kg/day PO divided q 8h is ordered for a child with a beta-hemolytic streptococcal infection. The child weighs 18 kg. Your bottle of Cephalexin is labeled 250 mg / 5 mL. How many mL will you give the child every 8 hours?

Answer 1

1.Given

Order: Ibuprofen

Frequency:4 times a day

Weight:8kg

Dose:10mg/kg

As 1kg=10mg

Then 8kg=??mg

Cross multiply and divide

=8×10/1

=8×10

=80mg

Available:100mg/5ml

Then 80mg=??ml

Cross multiply and divide

=80×5/100

=400/100

=4

Ans: The infant has to be given 4ml per dose

2.Given

Order:Cephalexin

Frequency:3times a day

Route:Per oral

Dose:25mg/kg/day

Weight:18kg

When 1kg=25mg

Then 18kg=??mg

Cross multiply and divide

=18×25/1

=18×25

=450mg

Therefore dose is 450mg/day

To calculate for 1 dose divide by 3

=450/3

=150

150mg/dose has to be given

Available:250mg/5ml

Then 150mg=??ml

Cross multiply and divide

=150×5/250

=750/250

=3

Ans: The child has to be given 3ml every 8 hour