lecture 16 - pediatrics Flashcards
give definition for paediatric ages
premature neonate : born before 37 weeks
neonate: up to 4 weeks
infant: 4 weeks to 1 year
child: 1-12 years
adolescent: 13-18 years
young adult: up to 24 years
what are pregnancy and fetal development age milestones
1st trimester: limb buds, primitive CNS, heart, organs form, head and facial development, early movement, sex apparent, circulation starts, some reflexes, free movement, kidneys work and foetus passes urine
2nd trimester: rapid skeletal development, movements felt
3rd trimester: most organs are capable of functioning, responds to sound, wrinkled eyelids re-open, respiratory movements, fat and iron storage, body hair dissepaers, body contours rounded, skull firm
what are medicine related issues in children ?
lack of licensed drugs
dosage requirements
unsuitable formulations
considerations of administration
what are examples of unlicensed medicines ?
extemporaneous dispensing, pharmaceutical ‘spreads’, importing medicines licensed in other countries, ‘named aptient’ supplies, chemicals not licensed at all for human use
what are examples of off label medications
dose, age of patient, indication, route of administration, contraindications
what are formulations or excipients that can cause issues in paediatrics ?
benzyl alcohol and methylparaben
propylene glycol
lactose
sugar and sorbitol
alcohol
what are Absorption considerations in paediatrics ?
Intestinal transit reported to be shorter, particularly for poorly soluble drugs or sustained release products
Gastric pH is neutral at birth - acidic values comparable with adults at 2 years
Bile secretion in the first 2–3 weeks of life is known to be poor
Intestinal permeability is reported to be high at birth with progressive reduction during the first week of life
what are distribution considerations in peaditrics
Lipophilic drugs have a relatively larger volume of distribution in infants compared with older children owing to their higher comparative levels of fat
Hydrophilic drugs also have larger volumes of distribution in preschool children as extracellular water decreases during development
In newborns, total plasma protein concentrations are 86% of adult values, so greater free fractions of these drugs are circulating and thus are able to penetrate various tissue compartments
what are metabolism considerations in paediatrics ?
Hepatic clearance of drugs can be higher in infants and preschool children as liver blood flow is increased compared with adults
Differences in enzyme expression and activity can result in altered metabolism of drugs or production of metabolites in paediatric populations that are not observed in adults
what are excretion considerations in paediatrics ?
The glomerular filtration rate (GFR) is 2 to 4 ml min in term neonates, and it doubles by 1 week of age, reaching adult values by the end of the first year of life
This effect is particularly important in premature infants, in whom renal clearance can be very low.
Renal excretion of unchanged drug is generally lower in newborns owing to the immaturity of renal function.
However a similar or greater rate of renal excretion has been observed in infants and preschool children compared with adult values for some drugs
