13 - Special Populations Flashcards
(47 cards)
What are special populations?
- Infants and children
- Elderly people
- Pregnant and breastfeeding women
- Obese, underfed
- Clinical issues (liver failure, kidney failure or dialysis, extracorporate membrane oxygention, therapeutic cooling)
What makes special populations different?
- Different PK and PD
- Different diseases
- Use different drugs
- High potential of damaging self or other (pregnant/breastfeeding)
Why should special populations be treated differently?
- Less info about safety and efficacy
- More complicated prescribing and dispensing
- Higher risk of adverse drug events
- Higher risk of ineffective therapy
What is ontogeny?
Development of an individual from the earliest stage to maturity
What do absorption and distribution describe?
How drugs get in the body and where they go
How are drugs absorbed in children?
- Oral
- Sublingual
- Intramuscular
- Percutaneous
- Rectal
What are some factors that influence oral drug absorption?
- Biliary function
- Gastric emptying time
- Intestinal motility
- Microbial colonization
- Intestinal drug transport
- Intestinal surface area
- Gastric pH
- Splanchnic blood flow
What is distribution?
Apparent “space” where a drug molecule may travel to or reside in
What are some factors that influence distribution?
- Extent (size of body water/adipose compartment; degree of plasma/tissue protein binding; permeability of cell membranes; acid-base balance
- Rate (regional blood flow; organ perfusion pressure; cardiac output)
What do metabolism and elimination describe?
Getting rid of foreign molecules
What is drug clearance?
- Volume of blood cleared of a substance per unit of time
- Relates to drug removal from the body by physiologic or extracorporeal methods
What is total clearance?
Additive term comprised of each route of metabolism or elimination (ex: kidney, bile, lung)
What are some factors that affect drug metabolism?
- Herbal medicine (ex: St. John’s Wort)
- Disease
- Drugs
- Genetics (ex: fast or slow metabolizers)
- Age
- Nutrition (ex: grapefruit juice)
What can cause increased toxicity and decreased toxicity in children?
- Increased toxicity b/c of immature glucuronidation
- Decreased toxicity b/c immature CYPs (ex: CYP can’t produce toxic intermediate of acetaminophen)
Can half life of a drug change w/ age?
Yes, can be longer the younger a child is
Can an adult dose of a drug simply be scaled based on body weight or surface area for a child?
No b/c doesn’t account for developmental changes that affect drug disposition or tissue/organ sensitivity
Why is pediatric prescribing more complicated than prescribing for adults?
- Specific and general aspects of pediatric px (side, immaturity)
- Limitations of commercially available dosage formulations
- Challenges of administering drugs
- Lack of info about drug use in children
- Inadequacy of clinical pharmacology training
What are the major principles of drug therapy in children?
- Prescribe judiciously
- Carefully select safest dosage regimen available
- Educate px, caregivers, and staff about the choice and expected positive and negative effects
- Carefully monitor px responses to therapy
When can prescriptions be considered as given “off-label”?
When given for a different age group, dosage, indication, dosage form, or route of administration
Why are the majority of pediatric drugs prescribed off-label?
- Lack of appropriate safety and efficacy data
- Shortage of child-friendly formulations
- Labels out of date
What are some general considerations that should be made w/ pediatric formulations?
- Administration route
- Adequate palatability
- Tablet size
- Liquid formulations require dosing device and preservative
What are the various sizes of tablets and what is the age limit for each?
- Small tablet = 3-5 mm diameter; children 2 y/o and older
- Medium tablet = 5-10 mm diameter; children at least 6 y/o
- Large tablet = 10-15 mm diameter; children at least 12 y/o
- Very large tablet = 15 mm or more diameter; adults 18 y/o and older
What are the max recommended single dosing volumes for various age groups of children?
- Max of 5 mL for children under 4 y/o
- Max of 10 mL for children 4-12 y/o
What is normally the max number of drops per single intake?
10 drops
