Chapter 6 Pharmacology

8/13/2019 Chapter 6 Pharmacology

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Chapter 6 :Life span : Children


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Pediatric PatientPharmacotherapeutics

Not all drugs have been tested in pediatrics

All pediatric drug dosages are calculatedindividually by weight in Kilograms

BSAbody surface area is also used

( external surface of the body in square

meters) Calculated using a formula or a tool

( normogram)


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What is the definition of a

Pediatric Patient The book defines the pediatric patient as:

A. Less than 12 years of age and under 30 kg

B. Less than 14 years of age and under 40 kg C. Less than 16 years of age and under 50 kg

D. Less than 18 years of age and under 60 kg


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Pharmacotherapeutics Therapeutic indications and effects for many drugs

are similar for children and adults. However, not all drugs that are labeled as safe for

adults have been labeled as safe for children. An estimated 75% of drugs regularly prescribed to

children in the United States have never beenlabeled for use in any pediatric population.

It is now considered unethical to excludechildren

from drug studies. Until all drugs have been tested and labeled for

use in children, nurses need to be aware that off-label use will occur.


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Question ? Calculate the correct dosage of the

following drug: child weighs 20

kilograms; the PDR states that thepediatric dosage for 30 mg/kg/day is

A. 200 mg/day

B. 300 mg/day C. 600 mg/day

D. 800 mg/day


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Answer Calculate the correct dosage of the

following drug: child weight 20

kilograms; the PDR states that thepediatric dosage for 30 mg/kg/day is

C. 600 mg day

20 kg x 30 mg/kg/day = 600 mg/day


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Pediatric patientPharmacodynamics

Mechanism of action is the same

Difference is: the ability of the childsbody organs to function fully ( howmature they are)

Younger the child = more immature thebody organs


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Pediatric Patient Pharmacokinetics

AbsorptionInfants GI tract less acidic

Absorption via IM or sc absorption of topical meds

Distribution- affected by:

body water

fat

immature liver function

immature blood /brain barrier


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Pediatric PatientPharmacokinetics

Metabolismimmature liver =

metabolism

Excretionoccurs in the urine musthave:

mature renal system

e.g. neonate = immature renal system :decrease dosage


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Pharmacokinetics A childs age, growth, and maturation can

affect how the body absorbs, distributes,

metabolizes, and excretes a drug. The nurse can help maximize the therapeutic

effects of a drug and minimize adverseeffects.

Dosages must often be lowered to accountfor immature or impaired body systems inneonates and infants.


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Absorption In the pediatric patient, age, disease process,

dosage form, route of administration, and foodsand drugs present in the childs body have an

effect on drug absorption. The infants gastrointestinal (GI) tract is less acidic

and thus has a higher pH than that of an adult. As the GI tract matures, the gastric pH decreases

and the GI tract becomes more acidic, reaching

adult values at approximately 1 year of age. Route of administration also affects absorption. Compared with adults, infants and children have a

greater body surface area.


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Distribution

In a pediatric patient, drug distribution processescan differ from those in an adult.

Differences in body water and fat Compared with adults, children have a higher

concentration of water in their bodies and a lowerconcentration of fat.

Immature liver function

The neonates immature liver produces fewer plasmaproteins.

Immature bloodbrain barrier At birth, the bloodbrain barrier is not fully developed.


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Metabolism

The immaturity of the neonatal and infantliver results in decreased or incompletemetabolism of many drugs.

A child with an immature liver orcompromised liver function is at risk for drugtoxicity.

Drugs requiring oxidation for metabolism are

frequently more rapidly metabolized inchildren than in adults because children havea faster resting respiratory rate and metabolicrate


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Excretion

In children with impaired renal function, drugdosages should be altered to achieve andmaintain therapeutic drug levels.

The neonate, especially the preterm infant,has immature kidneys, and renal excretion ofdrugs is slow.

A few drugs are excreted through the biliary

tree into the intestinal tract. Biliary blood flow is decreased during the first

few days of life.


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Contraindications andPrecautions

Most drugs prescribed to children areprescribed off-label.

Off-label usage therefore requires cautiousadministration and careful, frequentassessments of the child.

Some drugs are known to be dangerous inchildren and are labeled as such.

The core drug knowledge must bedetermined for each drug before the drug canbe administered to a child.


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Adverse Effects and DrugInteractions

More severe and more likely to occur inchildren because of the immature bodysystems of children.

Newborns and young children mayexperience serious adverse effects eitherfrom direct administration of a drug orthrough their mothers use of a medication.

Other adverse effects on body systems occuronly at specific phases of development.


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Developmental Considerations:Birth to 12 months

Some infants swallow a liquid drug through abottle nipple.

Drugs in rectal suppository form may begiven to infants

IM injectionsmallest gauge needle and

shortest length The preferred IM injection site for infants and

children up to age 3 years is the vastuslateralis.


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Developmental Considerations:Toddler ( 13 months to 3 years)

Toddlers can swallow liquid forms of drugs, and oldertoddlers can chew oral drugs.

Toddlers experience anxiety when separated from

their parents. Having a parent nearby helps with the childs

cooperation

Toddlers are anxious or uncooperative duringadministration of rectal suppositories {because of

their experiences with toilet training and sphinctercontrol.}

The vastus lateralis and rectus femoris remain the IMinjection sites of choice for toddlers.

Scalp veins are appropriate for IV therapy up to age18 months.


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Developmental Considerations:School Age Child ( 6- 12 Yrs)

Often very cooperative.

Offer choices to help exercise control.

Takes pride in accomplishments, such asreceiving an injection without incident.

Oral drugs may be given in liquid form,chewable tablets or pills.

The ventrogluteal site is recommended for anIM injection in the school-aged child.


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Developmental Considerations:Adolescent ( 1316 yrs)

Offer control whenever possible, allow choices

Sensitive about their bodies and theirindependence.

Routes of administration are similar to those foradults. Oral forms of drug therapy include tablets or pills.

Suppositories can be used, but the adolescent is likely

to be embarrassed. IM injection sites are usually the same as for adults

unless the adolescent is particularly small.


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Lifestyle, Diet and Habits

Infants primary food intake is milk and formula.{These substances decrease acidity and thusincrease gastric pH}.

In school-aged children and adolescents, assess forthe use and abuse of substances such as:

caffeine, alcohol, tobacco, and street drugs.

.

Question the parent regarding the use of herbaltherapy.

Consider economic circumstances of patient andfamily.


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Environment

Safety and storage of medications

Must have a parent or guardianresponsible for ensuring that the childreceives the prescribed therapy.


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Maximizing Therapeutic Effect

Administering drugs safely and effectively tochildren requires an understanding of

Pediatric anatomy and physiology

Developmental and cognitive levels

The diagnosis and prognosis

Oral drug therapy

Although usually not painful, administration of oralmedications can be traumatic

Work carefully with the child to ensure that all of thedrug is taken


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Preventing Medication ErrorsIn Pediatric Population

Most likely to occur in the followingsituations:

Younger than 2 years old In intensive care units

In Emergency Departments

Children who are receiving chemotherapy

Children who are receiving IV medication

Children whose weight was not documented


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Preventing Medication Errors

Most of the problems in dosagecalculation are related to the following:

Inability to identify the correctmathematical calculation

Poor math skills related to using fractions,percentages, decimals, and ratios

Infrequent use of calculation formulas Inexperience in applying dosage calculation

formulas to actual clinical practice


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Preventing Errors in PediatricPatients

Strategies for preventing medication errors:

Always weigh the child before administering any

medication Standardize as much as possible

Use computerized drug order entry systems

Use reliable drug information sources

Double-check each calculated dose for accuracy Measure and deliver oral medications via oral

syringes only.


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Reducing Psychological Stress

Some adverse effects in pediatric drug therapy involvepsychological distress of the child or parent.

Consider age-related emotional needs when selecting

appropriate communication techniques. For school-aged children and adolescents, address

feelings and discuss and answer questions as simply andhonestly as possible.

Play therapy is useful for reducing a childs anxiety and

promoting understanding of drug therapy. For preschoolers and school-aged children, take care to

explore the childs experiences with the health caresystem.


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Patient and Family Education

Provide honest and detailed explanations andrationales.

Education for infant patients is directed solely towardthe parent. For toddlers, fully explain the rationale for drug

therapy and the type of administration in private,away from the toddler.

Preschoolers require simple explanations. The school-aged child can understand somewhat

more in-depth explanations and will ask questionsregarding drug therapy.

Adolescents are treated like adults with regard to full

explanations and rationale for drug therapy

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Chapter 6 Pharmacology