Question

Jenny is a 4 year-old and was admitted in critical condition. The MD has ordered Penicillin 30 mg/Kg IVPB q 6 hrs for 4 doses as a loading dose; then decrease to 30 mg/Kg/day in 4 equal doses. The maximum safe dose is 25 mg/Kg/day. Jenny weighs 38 pounds. The pharmacy sends Penicillin 3 Gm vials labeled 3.7 mL = 800 mg. Calculate all doses to the nearest hundredth.

Answer 1

Given

Medication :Penicillin

Route:IV

Weight :38 pounds =17.2kg or 17 kg

Dose and frequency: 30mg/kg/day ,6hrly for 4 doses as loading dose

When 1kg =30mg

Then 17kg=??

=510mg (cross multiply and divide 17×30÷1)

Then 1 dose =127.5 or127mg (510÷4)

Loading dose is 127mg for first 4 doses

Then

Order 30mg/kg for 4 doses =127mg÷4=31.75 or 32 mg

In a day 32mg /dose as to be administered for 4 equal doses

Available

Penicillin =3Gm (3000mg)

3.7ml=800mg

Then the loading dose of 32mg=??

= 0.5(127×3.7÷800)

So 0.5ml  as to be administered as loading Dose

And thereafter

For 32mg

=0.14 or 0.1 ml (32×3.7÷800)

After 4 loading doses 0.1 ml has to be administered every 6 hrly (i.e., 4 doses)