Pediatric and Geriatric Pharmacology Flashcards
(33 cards)
Today around 50% of medications approved for adults have
pediatric safety and efficacy data
What factors affect drug absorption in young children compared to older children/adults?
- Gastric acid secretion ↓ (takes ~1 year to reach adult levels)
- Bile salt formation ↓ (affects fat-soluble drug absorption)
- Gastric emptying time slower
- Intestinal motility different
- Bowel length & absorptive surface are still developing
- Microbial flora immature and changing
What factors affect drug distribution in young children compared to older children/adults?
- new born total body water is 80% (55% adult)
- plasma protein binding lower in newborns (lower affinity –> less plasma)
- body lipid content is lower (3% pre-term)
what is the risk associated with sulfonamides in newborns?
risk of kernicterus due to low plasma protein binding
what effects does plasma protein binding have on Diazepam in children and adults?
Normal dose: 300 g/L
- adults: have 98% bound—> 6 g/L are free (active)
- child: have 90% bound –> 30 g/L free (active) –> 5x the normal amount is free which leads to more sedation
How are drug metabolizing enzyme activities effected by age groups?
less in neonates, children and older adults
How are renal functions effected by age group?
glomular filtration, tubular secretion and renal blood flow are lower in neonates and children
How is cardiac output effected by age group?
lower in older adults (how much drug is flowing in the body)
What is the difference in half lives of drugs in neonates vs adults?
neonates generally have LONGER half lives
**theophylline: toddlers will have shorter half lives than adults
How does BSA effect dosing regiments?
children have a greater BSA than adults so doses must be reduced (BSA is inversely proportional to height)
What drug has an adverse effect on teeth?
tetracycline
What syndrome might result in children with viral illnesses and take acetylsalicylic acid?
Reye Syndrome - progressive encephalopathy with hepatic dysfunction
What are the drugs that cause Stevens-Johnson Syndrome?
PCP LAPSE
- phenytoin
- carbamazepine
- phenobarbital
- lamotrigine
- allopurinol
- penicillin
- sulfa drugs
- erythromycin
What is given to a child to induce vomiting if they have ingested something bad?
syrup of ipecac
What are the physiological changes associated with aging?
- decline in normal body maintenance and function
- cardiovascular, respiratory, GI, genitourinary, endocrine, CNS and others all become less efficient with advancing age
- Decline in organ function ➭ health problems ➭ require drug therapy
What are the age related physiological changes of the GI?
- Diminished salivation Esophageal
- motility disorders
- Decreased Gastric acidity
- Decreased Gastric emptying time
- Decreased GI blood flow
How do GI changes in older adults impact drug absorption?
- Difficulty swallowing oral solid dosage form
- Dry mouth symptoms
- Decreased drug absorption
What are the age related physiological alterations that effect drug distribution?
- Decreased body size
- Decreased lean body mass
- Increased body fat
- Decreased body water
- Decreased serum albumin
What are the impacts from age related physiological alterations that effect drug distribution?
- Decreased dosage requirement
- Increased volume of distribution of fat- soluble drugs
- Decreased volume of distribution of water- soluble drugs
- Increased free fraction of drug in serum
What are the physiological/pathological changes associated with age related alterations in hepatic metabolism?
- Decreased Liver Mass
- Decreased Liver Blood Flow
- Decreased Hepatic Metabolism
What are the impacts from age related physiological alterations to hepatic metabolism?
Reduction in Drug Metabolism…. To active or inactive metabolites
How are Phase I and Phase II liver pathways affected in older patients, and why does it matter?
Phase I (P450 system): Involves oxidation, reduction, hydrolysis (makes drugs active/inactive)
- Unpredictable in older adults due to decreased liver function.
- ⚠️ Higher risk of drug accumulation and drug-drug interactions.
Phase II (Conjugation pathways): Adds groups (like glucuronide) to make drugs more water-soluble for excretion.
- Generally less affected by age but slows slightly.
- ✅ Preferred in older patients because it leads to non-toxic, easily excreted metabolites
How does aging affect kidney structure and function?
Structural Changes:
- Fewer nephrons
- Nephrosclerosis /Glomerulosclerosis: Hardening of small renal arteries
- Kidney shrinks in size
- Renal cysts may develop
Functional Changes:
- ↓ Glomerular Filtration Rate (GFR) → slower drug clearance
What physiological changes occur to the renal system due to aging?
- Decreased Kidney Mass
- Decreased Renal blood flow
- Decreased Renal tubular function
