1

Paediatric Pharmacy Practice

2

20 to 25% of total world populationPoorly developed organ functions and highest risk of toxicity and poor clinical response.Sulphanilamide elixir- death: Thalidomide tragedy.

Taste of Raspberries, Taste of DeathThe 1937 Elixir Sulfanilamide Incident

3

Why Do We Need PaediatricPharmacists?

Children are at increased risk of adversedrug events (ADE’s) Pharmacologic factors

•Age-based variability in absorption,distribution, metabolism, and excretion

ofdrugs

Physiologic factors•Weight and/or body surface area

(BSA) needto be considered for each drug for eachpatient

4

Process factors•Individualized dilution of stock

medicationsand fluids •Multiple concentrations of same drug• Dilution errors

Environmental factors•ICU settingWeight-based dosing

Error dosing rate Error rates inversely related to size or

weight of patient

5

Paediatric medication orders are more proneto errors than adult orders Doses are not standard Math errors can occur when calculating the dose Suspensions often have to be compounded Tablets may have to be cut Dilutions need to be made to make amounts that are measurable However, children have less tolerance for errors

6

Preemie <37 weeks gestation (gestationalage is the time from conception until Birth)

Full Term 37-42 weeks gestation

Neonate First 30 days of lifeInfant First year of life Toddler From 1 to 2 years of lifeChild Age 3-11 Adolescent Age Age 12 on

Definition of a child is based on age

7

Special Challenges of Practicing in Pediatrics

Lack of published information on therapeutic uses and monitoring of drugs Lack of FDA approval for many drugs used in pediatrics Lack of appropriate commercially available dosage forms and concentrations of commonly used medications Inability of patients to communicate withcaregivers Interacting with parents

8

Skills Necessary Dosage calculations Dosage-form selection Specialized drug preparation and administration techniques Understanding of PK/PD changes occurring with age Understanding of disease-specific conditionsaffecting drug choice or dose Understanding nature of medication errors inpediatric patients

9

Role of the Paediatric PharmacistEnsure the patient receives the necessary drug in a manner that allows the intended therapeutic effect to be realized.

10

Patient interviews Medication history

•Inquiring about OTC and herbal medications Allergy history

•True allergic reaction? Immunization history

•Can make recommendations to MD if patient is not up-to-date on immunizations

11

Discharge counselling Administration & use of appropriate

measuring device dosage Preparation of form at home, if necessary Attention to taste of liquid medications Prevention of accidental ingestions School / day-care issues directed at patient and/or caregiver

12

Drug Information Influence selection of drug therapy in initial phase of patient care

•Consult with physician and patient Provide current, unbiased and relevant drug information Assist with finding literature supporting use of drugs for unlabeled indications

13

Therapeutic Drug Monitoring Understanding timing / indication of monitoring to prevent unnecessary blood draws on children Account for age-related differences indosage Documentation in patient chart Monitor steps of the medication use processReduce drug costs Avoidance of medication errors resulting from over- or underdosing

14

Reduce Medication Errors Report medication errors Encourage others to report medication errors or suspected ADE’s Participation in quality-improvement committees Develop and enforce policies and procedures for safe medication practices

15

Drug Use Evaluation Low therapeutic index drugs

Those responsible for serious medication errors High frequency of preventable adverse drug reactions Expensive medications

Education Patients Nursing unit staff Physicians Pharmacy students and residents

16

Research Pediatric patients are “therapeutic

orphans” Insufficient research in pediatric patients Expansion of adult diseases into the pediatric population (i.e. AIDS) Use of therapeutic agents in children without FDA approval

17

Pharmacokinetic considerations

18

Absorption– Gastrointestinal pH- gastric acid output maturity is related to postnatal age andapproaches adult values by 3 months of age GI motility- neonates have a delay in gastric emptying time, adult values are reached at 6-8 months of age GI contents- develops rapidly within the first year of life, underdeveloped flora can increase absorption of drugs (digoxin)–

19

Percutaneous Absorption is increased in the newborn due to immatureepidermal barrier and increased skin hydration during the first 2 weeks of life Increased surface area to weight ratio increases percutaneousabsorption

20

Distribution–Body Water• Neonates are 80% body water compared to 55% in adults• Vd is increased for drugs that distribute to aqueous parts of the body (aminoglycosides)• Total body fat is 1% in a 29 wk neonate• Total body fat is 15% in a full term baby• Total body fat is 20-25% in 2yo toddler• Fat content tends to increase between 5-10 years followed by a decrease through age 17• Vd is increased for drugs that are highly lipid soluble

21

– Plasma Protein Binding• Neonates have decreased plasma protein which increases unbound concentrations (ex: Phenytoin may only be 70% bound in a neonate compared to 90% in an adult)– Blood Brain Barrier• An immature BBB due to incomplete CNS myelination results in increased CNS drug penetration

22

Metabolism– Neonates have decreased activity of many enzyme pathways, that is why drug dosages are decreased for neonates P450 activity is 50% of adult levels Decreased hydroxylation activity leads to decreased metabolism of phenobarbital, phenytoin, lidocaine Children have increased hepatic enzyme activity between 2-4 years of age. This may be due to large liver size compared to total body weight. Doses are increased during this time for theophylline, phenytoin, and phenobarbital.

23

At birth, kidney function is decreased, GFR matures first, then tubular secretion, and lastly tubular reabsorption GFR at birth is 2-4 ml/min, which is 0.5% of an adult level After the first week of life, a significant increase in GFR is seen, this explains why recommended doses change after 7 days of lifeAt 1 year, GFR reaches 70 ml/min/m2 Around 12-24 month of age, GFR and tubular secretion are more mature than tubular reabsorption and cause an increased renal clearance of drugs (digoxin)

Excretion

24

Administering Medications to Children

25

•  Safe pediatric dosages calculated by: –  Body weight

•  Measured in mg per kg, mcg per kg, etc. –  Body surface area (BSA)

•  Measured in m2

Remember 1 kg = 2.2 lb –  When converting pounds to kilograms, round kilogram weight to one decimal place

•  Tenths 1 lb = 16 oz

26

Dosage is optimally calculated by using thechild’s body weight or mass and the appropriate dose in milligrams per kilogram (mg/kg). A. Fried’s rule for infants age (in months) X adult dose ............................ =

dose for infant 150

27

age (in years)............................. X adult dose = age (in years) + 12

dose for child

Young’s rule for children 2 years old or older

weight (lb) X adult dose........................................ = dose for child 150 lb (avg wt of adult)

Clark’s rule

28

BSA of child (m)2 X adult dose ............................................... = 1.73 m2 (avg adult BSA)

approximate dose for child

Child’s dosage based on body surface area (BSA)

In the case of some drugs, such as chemotherapy, doses are based on body surface area (BSA). This value can be determined from the patient’s height andweight, using either a nomogram or the following equation:

height (cm) X weight (kg)BSA (m)2 = .......................................

3600

29

Although the total body water content of an adult accounts for approximately 60% of body weight, the total body water content of a healthy newborn is(A) 40%.(B) 50%.(C) 70%.(D) 80%.(E) 90%.

30

THANK YOU