A bottle of Pediatric Suspension contains 80.0 mL of medication. One teaspoon contains 65 mg of theophylline and 4.0 mg of phenobarbital.

Question

For frequent attacks of bronchiol asthma, the label recommends 1 teaspoon four times daily per 60. lb of body weight. (Given: 1 teaspoon=5.0 mL)

(a) Calculate the mass (in ‘mg’) of theophylline that a 90. lb child will receive in one day.

(b) Calculate the mass (in ‘grains’) of phenobarbital that a 90. lb child will receive in one day. (Given: 1 grain=64.80 mg)

(c) Approximately how many days will one bottle last for a 60. lb child?

Answer 1

Hi Kim,

First you going to determine, how many ml of suspension, a 90 lbs child will need on the basis that 60 lb child requires 5ml×4 teaspoon = 20 ml

( 20 ml/60lbs) × 90 lbs = 30 ml suspension

a) to determine amt of theophylline a 90 lbs child will take in a day,

( 65mg theophylline/5.0 ml) × 30 ml = 390 mg theophylline

b) To Determine mass of phenobarbital, 90 lbs child will take, Determine mass in mg first and then in grains

(4.0mg phenobarbital/5.0 ml)×30ml = 24 mg phenobarbital

(1 grain/ 64.80 mg) ×24 mg = 0.37 grain of phenobarbital

c) To determine how many days it will last to a 60 lbs child,

(× 1 day/20.0 ml)×80.0 ml = 4 days