peadiatric Flashcards
What is bioavailability?
fraction of an administered dose of
unchanged drug that reaches the systemic circulation
what influences oral absorption of Oral Medicines?
Gastric & Intestinal pH (gastric pH is less acidic in children)
Gastric & Intestinal transit time
GI content e.g. microflora
Disease/Illness e.g. diarrhoea
What happens to the bioavailability of weakly acidic drugs?
Bioavailability is reduced e.g. phenobarbital
what happens to the bioavailability of basic drugs?
Bioavailability increased e.g. penicillins
Explain the bioavailability of digoxin in 2-4-year-olds?
Bioavailability is reduced due to bacterial degradation in GI tract
what is bile and when does it develop in children?
(Bile = produced by the liver aids digestion of lipids/ fat-soluble molecules in the small intestine
develops during the 5 weeks its absent at birth
What factors affect drug distribution?
Vascular perfusion
body composition
tissue binding characteristics
plasma protein binding
what happens to total body weight, total body water and extracellular fluid as child gets older?
volume decreases so the dose of water-soluble drugs required is larger in newborn than older children
Distribution: Protein binding
drugs bind to proteins
protein binding limits free drug circulating in body
protein binding reduced in infants as they have less albumin and globulins
bilirubin and free fatty acids circulate in high concs in newborn which compete with drugs
explain level of protein binding by 3-year old
by 3, level of protein binding similar to adults for ACIDIC drugs
for BASIC drugs level similar to adult at 7-12 years
which enzyme involved in drug metabolism?
Cytochrome 450
CYP450
What does CYP450 do?
Inactivates drugs during phase 1 reactions; oxidation, reduction, hydrolysis
How is paracetamol metabolised in adults?
Metabolised via Glucuronidation
How is paracetamol metabolized in children?
Metabolised via Sulphate conjugation
What does renal elimination depend on?
Plasma protein binding
renal blood flow
tubular secretions
glomerular filtration rate
how are medicines administered if the child has difficulty swallowing or if the child is unconscious?
Medicines and enteral nutrition may be
administered directly into the stomach via a
nasogastric tube
what can high doses of corticosteroids lead to?
suppresses cortical axis and growth
What is the role of Aspartame and its adverse effects
Aspartame is an artificial sweetener
Its a source of Phenylalanine- should be avoided in Phenylketonuria
role of benzoic acid and its effect?
Benzoic acid is a preservative
jaundice in newborns (yellowing of the skin)
role of ethanol and its effect?
ethanol is a solvent leads to intoxication (impairments)
role of dyes/colorants and its effects for medicines?
dyes are used as colouring agents- causes hyperactive behaviour in children
role of glucose and sucrose and its effects?
glucose and sucrose are used as sweetener- it may lead to obesity and tooth decay
role of propylene glycol and its effect
propylene gylcol is a solvent has CNS effect e.g. seizures/agitation
role of sorbitol and its effects?
sorbitol is used as a sweetener- may cause osmotic diarrhoea and GI discomfort
what is phenylketonuria condition?
Phenylketonuria (PKU) is a rare but potentially serious inherited disorder. Children with PKU
can’t break down the amino acid phenylalanine, which then builds up in the blood and brain
leading to behavioural problems and seizures.
what is passive immunity?
Passive immunity is provided when a person is given antibodies to a disease rather than producing them through his or her own immune system
how can antibodies be transferred?
Naturally- from mother via placenta/breastmilk
Artificially- medically transferred
what is active immunity?
= immune system builds up overtime by an
individual = long lasting.
Naturally- after exposure to infection
Artificially- immunisation/vaccination
which Vaccines are administered at 8-weeks?
Diptheria with tetanus Pertussis Hepatitis B Poliomyelitis Haemophilus influenza type B Rotavirus
ALL FIRST DOSE
Which vaccines are administered at 12 weeks?
Diphtheria with tetanus Pertussis Hepatitis B Poliomyelitis and Haemophilus Influenza type B rotavirus ALL SECOND DOSE
Which vaccines are given at 16 weeks?
Diphtheria with tetanus Hepatitis B Influenza type B Poliomyelitis + haemophilus pertussis ALL THIRD DOSE AND Menigococcal group B -second dose
which vaccines are given to 1-year olds?
MMR- first dose
menigococcal group B- single booster
pneumococcal polysaccharide conjugate- single booster
haemophilus influenza type B with menigococcal group C- single booster
which vaccines are given to 2 year olds?
Influenza vaccine - Live nasal spray is recommended
