FALL 2012

ANSWERS TO PEDIATRIC MATH PROBLEMS (from questions p. 96 in NU 102 Course Manual)1. The doctors will order Ampicillin IVPB Q6H for a child who is 5 months old and weighs 12 2 lbs. Recommended dose: 200 mg/kg/24 hrs divided Q6H. How many milligrams of Ampicillin should be given for each dose? On hand is Ampicillin 250mg/ml. How much would you draw up to give?Step 1: Convert lbs. to kg.: 12.5 2.2 = 5.68 kg.Step 2: Multiply recommended dose by wt. in kg.: 200 mg. X 5.68 kg. = 1,136 mg/24 hrsStep 3: Divide total mg. by # of doses to be given per 24 hrs.: 1136 4 = 284 mg. Available- 250 mg/ml 284 mg 250 mg = 1.136 = 1.1 ml. Answer: 284 mg for each dose; Draw up 1.1 ml. (for amounts < 1 ml round to nearest hundredth; for amount greater than 1 ml round to nearest tenth)2. The order is for Cefotaxime (Claforan) to be administered IVPB Q6H for pneumonia. The child is one year and weighs 21 lbs. Recommended dose for Cefotaxime: 20 0 mg/kg/day divided Q 6H. Calculate the daily dose for Cefotaxime. Calculate the dose that can be given every 6 hours.Step 1: 21 lbs 2.2 = 9.5454= 9.55 kg.Step 2: 200 mg X 9.55 = 1,910 mg daily dose for ClaforanStep 3: 1,910 4 = 477.5 kg. dose to be administered at 6 hour intervals.

3. Clindamycin 400 mg IVPB is ordered for an 8 year old who weighs 66 lbs. The Recommended dose is: 24-40 mg/kg/24hr divided Q6H. Is this a safe dose? Available: 900 mg/6 ml. How much will you draw up from vial?Step 1: 66 lbs. 2.2 kg. = 30 kg.Step 2: 24 mg. X 30; 40 mg. X 30 = 720 1200 mg. daily safe dose rangeStep 3: 720 mg 4, 1200 mg 4 = 180 mg - 300 mg (safe dose range)The dose ordered is too high. Notify the physician to adjust the dose.

4. Bactrim 190 mg p.o. Q 12H is ordered for a child who is 4 years old and weighs 25.4 kg. The recommended dose is 7.5 mg/kg/dose (Q12H). Is this dose appropriate? Biaxin is available 250mg/5ml. How much will you draw up to give?Step 1: weight is already in kg.Step 2: 7.5 mg. X 25.4 kg. = 190.5 mg. Since the recommendation is per dose (not per 24 hrs) then the answer is 190.5 mg for the amount that can be administer every 12 hours.

5. The physician orders ranitidine (Zantac) IVPB to be given Q 8H. The child weighs 74 lbs. The recommended dose of ranitidine is 2 mg/kg/24 hrs divided Q 8H. Maximum dose not to exceed 50 mg/dose. How much should be ordered by the doctor for each dose. Ranitidine is available 25 mg/ml. How much will you draw up to give? Step 1: 74 2.2 = 33.64 kg. Step 2: 33.64 X 2 = 67.28 mg per 24 hoursStep 3: 16.82 mg 3 = 22.4 mg Draw up 0.9 ml.

6. A 15 month old child has a fever and the mother calls inquiring how much Motrin she should give. The child weighs 23 lbs. The recommended dose for motrin is 10 mg/kg/dose. Motrin is available in a suspension 100mg/5ml. How much would you instruct the mother to give?Step 1: 23 2.2 = 10.45 kg.Step 2: 10 X 10.45 = 104.5 mg per dose Step 3: The mother should be instructed to administer 5.2 ml

7. Dexamethasone will be ordered IVPB Q6H for a child who is 8 yrs. and weighs 53 lbs. The recommended dose is 2 mg/kg/day divided Q6H. Calculate the dose that will be ordered. Dexamethosone is available 40 mg/ml. How much will you draw up to give for each dose?Step 1: 53 2.2 = 24.09 kg. Step 2: 24.09 X 2 mg = 48.18 mg. per 24 hoursStep 3: 48.18 4 = 12 mg. dose that will be administered every 6 hours.The nurse will administer 0.3 ml for each dose.