Paediatric Clinical Pharmacology Flashcards
What is a childs response to medication affected by?
Their size, age, nutrition & maturity
In terms of pharmacology in the immediate postnatal period problems may arise through what?
In utero exposure & transplacental transfer of drugs to infant
Breast fed infants can be affected by their mothers medication
What are key prescribing points for paediatrics?
When prescribing drugs for children use the most simple dosage regimen.
Pay attention to formulation, route, and duration of therapy.
Involve parents in your prescribing choice
Always check with the BNFc
What are off label medicines?
Licensed for human use but not for use in children below a certain age such as 16 or 18 years or via a certain route or for a certain disease
What are unlicensed medicines?
Medicines that have no licence for human use in this country (This includes licensed medicines which are reformulated for easy use in children-extemporaneous preparations)
What are the reasons for off label prescribing and when is it done?
Formulation administered via a route not intended
Medicines used for an indication not intended
Medicines used at a different dose to that recommended
Children below stated recommended age limit
Medicines without a licence
including those made especially for the child or being used in clinical trials
What are the problems with prescribing in children?
Extrapolation from adult data is unsafe:
- Pharmacokinetic differences between adults and children
- Pharmacodynamic differences in responses
- Effects on growth and development not known
- Different specific pathologies
Lack of PIL/SPC information
Why are neonates/infants more sensitive to drugs than adults?
Due mainly to organ system immaturity
(Neonates/infants are at increased risk for adverse drug reactions & Young patients show greater individual variation)
The early post natal period (0-27 days) is a phase of physiological immaturity with what?
- rapid growth
- highly variable alterations in drug metabolism and elimination.
- lower tolerance to ADRs,
- difficulty in identifying efficacy and toxicity.
Higher incidence of therapeutic errors
Almost all medicines (98%) used during this phase are prescribed
and used off label
Infancy (1-23 months) is an extension of the first stage, but the type and severity of disorders being treated are different: what changes occur?
Body weight gain and body water composition change rapidly as does the ratio of bodyweight or surface area to organ size and function.
What is the toddler stage associated with?
This stage is associated with minor illnesses, leading to multiple short courses of therapy.
Problems with compliance
The young child (2-11 years) have what enhanced?
Enhanced metabolism and excretion
Clearance can change significantly during a single dose regimen.
About 30% of prescribed medicines are off label
What changes occur in the adolescent/young adult (12-18 years)?
Sexual development produces major changes in body size and composition which affect drug metabolism.
Psychological changes and peer pressure result in behaviour such as smoking, alcohol and elicit drug use which can alter drug metabolism.
How do paediatrics differ in terms of when they are given oral administration of drugs?
Reduced gastric acid and delayed gastric emptying. Adult levels reached at 3 years
Absorption via the GIT reaches adult values by 6-8 months.
Bioavailability of drugs with high hepatic clearance and first pass elimination is reduced and highly variable.
Drugs which rely on entero-hepatic circulation such as cyclosporin also highly variable.
Percutaneous (skin) administration: Is it enhanced in children?
Is enhanced in infants and children, especially with damaged skin or an occlusive dressing.
STEROIDS
