Drugs in paediatric populations Flashcards
What age is considered a neonate?
0-28 days old
What age is considered a infant?
1-12 months old
What age is considered a child?
1-12 yrs old
What age is considered a adolescent?
12-18 yrs old
Absorption: Discuss the gastric pH in neonates and children
Neonates = gastric pH of 6-8, pH drops to 1.5 and 3 (returns to neutral after) in first week of life –> enhanced absorption of acid-labile drugs
Child = by age 2, gastric pH is adult level
Absorption: discuss the gastric emptying time of neonates
Neonates and infants = prolonged gastric emptying –> impaired absorption and greater ADR risk
Absorption: discuss the peristalsis in neonates
Neonates = irregular and unpredictable peristalsis –> enhanced med absorption
How well do neonates absorption intramuscularly?
Variable or delayed in premi and new born
Discuss percutaneous absorption in neonates
Enhances skin permeability
Absorption inversely related to thickness of epidermal barrier
Discuss rectal absorption in neonates
incomplete and relatively slow
Regarding neonates, discuss the drug distribution in relation to body composition
Total body water is higher in infants, neonates, foetus, and children compared to adults
Body fat composition is lower in children
Do children require different doses for hydrophilic drugs?
Yes, they have lower body fat
Need higher doses in comparison to adults
Whilst children need lower doses of lipid soluble drugs
Discuss how protein binding is influenced in paediatric patients
Binding of drug to plasma protein is dec in neonates
Highly protein bound drugs = less bound in neonates compared to older children –> inc free or unbound drug –> more ADRs/tox
How does drug metabolism differ in paediatric patients?
Full hepatic metabolic capacity = 6 months to fully develop
Thus prolonged elimination half life = paracetamol, diazepam, indomethacin, theophylline, phenytoin
Morphine = higher doses in premature infant
WATCH FOR DRUGS W/ SATURABLE KINETICS
How does drug excretion would differ in paediatric patients?
Takes several weeks to 1 year for renal function to develop = renally cleared drugs will accumulate in infants
Thus slow elimination of digoxin, aminoglycosides, penicillin, cephalosporins
How does hepatic disease affect paediatric therapeutics?
Liver main organ for drug metabolism –> damage or disease –> decreased drug clearance
Cirrhosis and CHF –> dec clearance of drug w/ high extraction ratios
How does renal disease affect paediatric therapeutics?
Renal failure = dec dosage requirements of drugs renally excreted
Monitor serum concentrations closely
Generally, what factors effect/complicate paediatric pharmacotherapy?
adult concentrations (insulin, morphine, hydralazine, digoxin, atropine, etc.) may need to be diluted
Many drugs need to have altered routes of administration
Drugs will need to be crushed or mixed
Patient may refuse meds
Drug might be lost during administration
What factors influence paediatric medication adherence?
Poor communication (parent and med profesh)
insufficient prescribing info
lack of understanding about disease severity
fear of ADRs
failure of patient/parent to administer drug
inconvenient dosing forms
What are some common conditions in paediatric patients?
Epilepsy
Cold, cough, fever, nausea
asthma
diabetes
adverse mental health conditions (anxiety, depression, ADHD, sleep disorder, psychosis, OCD, tourette’s)
Outline the principle considerations of drug dosing in paediatric patients
Safe = not overdosing
Effective = sufficient to effect a cure/control disease/ relieve symptoms
Measurable = able to measure using tools that are readily available
What are exceptions to paediatric dose calculations?
Chemo doses = BSA
Liver, renal, other disorders that affect ADME
> 12 months if above/below average weight = use ideal body weight
When can paediatric dose calculations be rounded up?
If wide dose range, TI, max daily dosing
If sub-therapuetic dose is associated w/ ADRs
DONT GO OVER MAX DAILY DOSING
When can/should paediatric dose calculations be rounded down?
narrow therapeutic index drugs
How can tablets be modified if no liquid formulations are available?
dissolve or be dispersed in water
Check solubility in martindale
Check stability if solution is stored
How can injections be modified if no liquid formulations are available?
beware glass fragments
Some vehicles may be harmful
may be in suitable vehicle w. suitable pH
