Download Pharmacologic Management

Pediatric Pharmacology
JAN BAZNER-CHANDLER
RN, MSN, CNS, CPNP
BOWDEN TEXT BOOK CHAPTER 9
Developmental Considerations
• Pharmacokinetics
– Absorption
– Distribution
– Metabolism
– Elimination
• Pharmacodynamics: how drug produces physiologic
and biochemical changes
Absorption
 Gastrointestinal absorption
 Gastric pH is high in neonate
 Intestinal motility (transit time) is decreased in neonates and
increased in older infant and children
 Bile acid pool and biliary function is diminished in neonates
Absorption of Drugs
 Rectal
 Intramuscular- varies
 Topical / dermal – related to skin hydration
 Intraocular – thin membranes can cause systemic
effects
Distribution
 Neonates have a higher proportion of total body
water – related to water solubility of drug
 Lower portion of body fat – lower doses of lipophilic
drugs

Digoxin: drug books with have different dosing for the
neonates, infant and children
Digoxin Example
 IV children > 10 years (digitalizing dose): 8 to 12
mcg/kg given as 50% of the dose initially and ¼ of
initial dose each of 2 subsequent doses at 6-12 hour
intervals.
 IV infants 1-24 months (digitalizing dose): 30 to 50
mcg/kg given as 50% of initial dose and ¼ of initial
dose in each 2 subsequent doses at 6-12 hour
intervals.

Davis Drug Guide
Digitalizing Dose
 What does this mean?
Distribution Continued
 Protein concentration at birth is 80% of adult values
 Fetal albumin has limited drug binding ability
 High potential for toxicity
 Immature blood-brain barrier
 Drug to treat neonatal sepsis will penetrate the brain
 Drugs can accumulate in the brain tissue
Metabolism
 Newborn enzymatic microsomal system is less
effective
 Liver maturation varies
Elimination
 Glomerular filtration and tubular secretion are
reduced at birth
 Gradual increase in renal function to adult level
(about 1-2 years)
Nursing Responsibilities
Six Rights
 Right medication
 Right dose
 Right patient
 Right route
 Right time
 Right approach
Right Dose
• Drug dose calculated on weight in kilograms or BSA
• Adult dosages used in children who weigh more than
50 kilograms
• Double-check math calculations on all medication
given
• BSA is the most accurate way to calculate dosages
–
–
–
Used in calculating chemotherapy
Neonates
ICU
Dispensing Correct Dose
 Many drugs come in multi-dose containers
 Keflex 250 mg / 5 mL
 Amoxicillin 125 mg / 5 mL
 Acetaminophen comes in various concentration: 80 mg / 0.8
mL , 120 mg / 5 mL , 250 mg / 5 mL
Right Patient
 Identification by 2 sources
 All children need identification wristband
 Two person identification (parent / nurse)
 All mediation taken into room should be labeled with child’s
name, name of drug, and dose
 MAR

Is the mediation appropriate for the patient?
Right Route / Time
 Medications can be ordered po, sub-q, IM, IV
 Medications should be administered within ½ hour
before or ½ hour after prescribed time.

Problem if multiple intravenous medications ordered to be
given at the same time
Developmental Considerations
 Infant
 Administer medication before the infant feeds
 Offer med in small amount of formula or cereal / fruit
 Give via spoon or syringe
 Parent may give but nurse must be in the room and observe
medication being given
Developmental Considerations
• Toddler
– Simple explanation
– Small cup or spoon (syringe may be seen as a “shot”)
– Ask parent how child takes medication
– May need to restrain in lap and offer small amounts while
holding the cheeks together until child swallows the med
– If giving injection – have parent or another nurse assist
Conversions you need to remember
 1 teaspoon = 5 mL
 1 tablespoon = 15 mL
 1 ounce = 30 mL
 1 gram (g) = 1000 milligrams (mg)
 1 milligram (mg) = 1000 micrograms (mcg)
 1 liter (L) = 1000 milliliters (mL)
grains (gr) to milligrams (mg)
 gr 1 = 60 mg
 gr ¾ = 45 mg
 gr ½ = 30 mg
 gr ¼ = 15 mg
Measuring cup
How many mL in 4
teaspoons?
Calculations
 Pounds to kilograms
 Safe Dosing
 How to calculate medication dose using ration /
proportion
 IV medications
 24 hour fluid calculations
 Naso-gastric drainage replacement
Pounds to Kilograms
• Pounds to kilograms = pounds
2.2
Nursing Alert:
In pediatrics you need to carry out to the hundredths
(do not round)
Kilogram Example
 20 pounds 5 ounces
 First need to convert 5 ounces to a fraction of a
pound 5 divided by 16 = 0.31
 20.31 pounds divided by 2.2 = 9.23 kilograms
 Note medication would be calculated based on 9.23
kilograms. DO NOT ROUND
Pounds to kilograms
 If a child weights 6 lbs 6 ounces what is the weight in
kg?

6 ounces = 0.37 pounds
16 ounces

6.37 pounds divided by 2.2 kg = 2.89 kg
Medication dosage
 For a dosage of medication to be safe, it must fall
within the safe range as listed in a Drug Handbook,
PDR or other reliable drug reference.
Safe Medication Dose
 Calculate daily dose ordered (Physician orders)
 Calculate the low and high parameters of safe range
(from drug book)
 Compare the patient’s daily dose to see if it falls
within the safe range.
Calculation
 A child is 2 years and weighs 36 lbs
 Physician order: Amoxicillin 215 mg po tid for a
bilateral otitis media (ear infection)

First you would need to change 36 lbs to kg

36 divided by 2.2

Patient weight in kg = 16.36 kg
Calculating Safe Range
 Davis drug guide: PO (children) < 40 kg:
Amoxacillin 6.7 to 13.3 mg / kg q 8 hours.

(low range)16.36 x 6.7 = 109.6 mg q 8hours

(high range)16.36 x 13.3 = 217.5 mg q 8 hours
Safe Range
 109.6 mg to 217.5 mg of Amoxicillin Q 8 hours.
 Is the 215 mg dose ordered by the MD safe? Yes (it
falls within the safe range)
How much medication do you give?
Amoxicillin Suspension comes:
250 mg per 5 mL you want to give 215 mg



250 mg 215 mg
5 ml = x ml
1075
250x
Give 4.3 mL po every 8 hours
Nursing Alert
 Read the medication ranges carefully: dosing can be
for:

dose range for 24 hours

dose range for q 8 hours

dose range for q 12 hours
Fluid Control
 Crucial in the pediatric population
 Units often have policies that children under a
certain age are on a fluid control pump.
Fluid overload
 Know what the IV rate is.
 Hourly recording of IV fluid intake.
 Don’t try and catch up on fluids.
 Calculate fluids used to administer IV medications
into the hourly fluids amount
Daily Fluid Needs
 Fluid needs should be calculated on every patient to
assure that the infant / child is receiving the correct
amount of fluids.
 Standard formula for pediatrics needs to be
memorized.
Maintenance Fluid Requirement
 Up to 10 kg
 100 mL / kg/ 24 hours
 11 to 20 kg
 1000 mL + 50 mL / kg / 24 hours
 Greater than 20 kg
 1500 mL + 20 mL / kg / 24 hours
Bowden text page 740
Fluid Calculations
 Since children are in the hospital for various illnesses
they will often have increased fluid needs:
dehydration, fever, vomiting, diarrhea, inability to
take po fluids.
 24 hour fluid calculations may be 1 ½ to 2 times
maintenance.
Fluid Calculation
 7.27 kilograms
 100 mL x 7.27 kg = 727 mL
727 mL / 24 hours or 30
mL per hour
Fluid Calculation Problems
 9 pound infant
 9 pounds = 4.09 kg (always calculate to 100th)
 4.09 x 100 mL = 409 mL / 24 hours 0r 17 mL / hour
 1 ½ times maintenance = 1.5 x 409 = 613 mL / 24
hour or 25 mL / hour
Fluid Calculation
• 36 pound child
• 36 pound = 16.36 kg
• 10 kg x 100 mL = 1000 mL
• 6.36 kg x 50 mL = 318 mL
• 1318 mL / 24 hours or 55 mL / hour
• 1 ½ times maintenance = 1.5 x 1318 = 1977 mL / 24
hours or 82 mL / hour
Fluid Calculations
 52 pounds
 52 pounds = 23.63 kg
 100 mL x 10 = 1000 mL
 50 mL x 10 = 500 mL
 20 mL x 3.63 = 72 mL
 Total fluids = 1000 + 500 + 72 = 1572 mL / 24 hours
or 65 mL / hour
 1 ½ times maintenance = 1.5 x 1572 = 2358 mL / 24
hours or 98 mL / hour
Fluid Calculation
 64 pound child
 Convert pounds to kilograms = 29.09 kg
 Fluid calculations:
 100 mL x 10 kg = 1000 mL
 50 ml x 10 kg = 500 mL
 20 ml x 9.09 kg = 181 mL
1681 mL / 24 hours or 70
mL / hour
IV Medications
Key concepts
 Time over which a medication should be
administered is critical information
 Minimal dilution (end concentration of medication)
is important for medications such as
aminoglycosides).
 Therapeutic blood levels
Buretrol or Volume Control Chamber
Total of medication in chamber + 20 ml IV fluid
needed to flush the medication.
Page 316 Bowden text
IV Buretrol
 A buretrol or volutrol is an inline receptacle between
the client’s IV catheter set and the bag of fluids.
 Capacity is 120 to 150 mL
 Rationale: the nurse can fill the buretrol to a certain
level and if the IV pump malfunctions, only the
volume in the buretrol will flow to the client.
Nursing Alert
• If the IV medication is not “flushed” with 15 to 20
mL of fluids the medication will still be in the line
and could be a problem
–
–
–
If IV rate is KO (5-10 mL per hour) the medication in the
tubing would take 2 to 4 hours to get to the patient
If you are giving two or more IV medications the drugs could
be mixed in the tubing if the appropriate flush is not done
* THE MD ORDERS WILL NEVER INCLUDE THE
FLUSH IN THE ORDER
Nursing Alert
 Include the extra fluid given to administer IV
mediations and fluids used to “flush” the tubing in
the calculation of the child’s total fluid intake.
Flushing buretrols / solusets
 http://www.iv-therapy.net/node/1319
 Two great articles that explain the concept of
“flushing” the line after giving an IV medication
Syringe Pump
Calculation of fluids needs to include
the fluid in the syringe + the fluid in
tubing.
•4 mL of medication + 5 mL in tubing
•9 ml of fluid in total
Syringe pumps
 http://www.youtube.com/watch?v=clh6kPXhOlE
Parenteral Pediatric Medications
 Step 1: Convert lb to kg
 Step 2: Determine the safe range in mg/kg
 Step 3: Decide whether the dose is safe by comparing
the order with safe dose range
 Step 4. Calculate the dose needed
 Step 5. Check reference for diluent and duration for
administration.
Clinical Judgment 9-1
 Bowden Textbook page 217
 2nd Edition
Example #1
 Child: 5 years: weight 44 lbs
 Order: famotidine (Pepcid) 5 mg IV bid
Drug Guide Information
 Usual Dosage:
0.5 mg / kg / day divided twice daily (maximum
40 mg / day)
 Administration: May be administered IV push over
a period not less than 2 minutes or as an
intermittent infusion over 15 to 30 minutes; final
concentration not to exceed 4 mg/mL.
Example #1
 Convert pounds to kg: 44 lb = 20 kg
 Determine safe dose:
 20 kg x 0.5 mg = 100 mg
 100 mg divided by 2 (drug is given twice a day)
 5 mg is safe it meets mg / kg rule and does not exceed 40
mg/day.
 5 mg bid = total of 10 mg/day
Example #1
 Calculate the dose
 Pepcid is provided as 10 mg/mL
 10 mg = 5 mg
1 mL
x mL
5 =
10x 0.5 mL of Pepcid
Example #1
 Calculate the dose
 Pepcid is provided as 10 mg/mL
 10 mg = 5 mg
1 mL
x mL
5 =
10x 0.5 mL of Pepcid
Example #2
 Child: 4 years: weight 17 kg
 Physician order: Fortaz (Ceftazidime) 280 mg IV q 8
hours
Drug Guide Information
 Dosing:
 Safe dose 30 to 50 mg/kg/day
 Drug supplied as 1 gram powder. Directions: Dilute
with 10 mL of sterile water to equal 95 mg/mL.
 Administration: intravenous infusion over 15 to 30
minutes; may be given IV over 3-5 minutes at final
concentration of 100 mg/mL
Example #2
Safe dose is 30 to 50 mg/kg/day
• Low range: 17 kg x 30 mg = 510 mg/day
• High range: 17 kg x 50 mg = 859 mg/day
Safe range is 510 to 859 mg/day or 170 to 286 per
dose.
If the order is to give the drug q 8 hours you would
need to divide the safe range by 3 or multiple the q 8
hour dose x 3.
Example #2
Drawing up the medication:
1 gram / 10 mL or 95 mg / 1 mL
95 mg = 280 mg
1 mL x mL
280
95x = 2.94 mL or 2.9 mL
DO NOT ROUND UP TO 3 mL
Example # 2
 Adding medication to the volutrol
 Take the 2.9 mL of Ceftazidine – inject it into the
port on the volutrol and add additional IV fluid to =
10 mL.
Replacing NG Fluid Loss
NG – cc/cc replacement
 If a child has a nasogastric tube that is draining fluid
the physician will often write and order for:

NG drainage – cc/cc replacement q 4 hours
What does this mean?
Nasogastric Output
 NG output is measures q 4 hours.
 At the beginning of the shift the night nurse reports
that the drainage was 150 mL for the last 4 hours and
you need to replace this over the next four hours.
 Note: this is in addition to the IV hourly rate
ordered.
Sample problem
 IV hourly rate is 115 mL/hour
 NG output to be replaced over the next 4 hours is 150
cc’s or 37 mL/hour.
 IV would be set at 115 mL + 37 mL = You would run
the IV at 152 mL / hour for the next four hours.
Practice Problems
 Do the practice problems.
 Can be done individually or in groups.
 Testing will be on like problems.
 You must achieve 90% or better to be able to safely
administer medications in the clinical setting.