Special Populations Flashcards
Drug therapy during pregnancy
- drugs cross the placenta by diffusion
- factors affecting safety: drug properties, fetal gestational age, maternal factors
- FDA has implemented pregnancy safety categories
- FDA now requires pregnancy labeling to be included in packages inserts
category A
controlled studies in humans show no risk to the fetus
category B
no controlled studies have been conducted in humans; animal studies show no risk to the fetus
category C
no controlled studies have been conducted in animals or humans
category D
evidence of human risk to the fetus exists; however, benefits may outweigh risks in certain situations
category x
controlled studies in both animals and humans demonstrate fetal abnormalities; the risk in pregnant women outweighs any possible benefit
Drug therapy during breastfeeding
- breastfed infants are at risk for exposure to drugs consumed by the mother
- drug levels in breast milk are usually lower than those in the maternal circulation
- consider risk-to-benefit ratio
Neonatal and pediatric absorption
- gastric pH less acidic until 1-2 years of age
- gastric emptying slowed
- IM absorption faster and irregular
Neonatal and pediatric distribution
- greater total body water means lower fat content
- decreased level of protein binding
- immature blood-brain barrier-more drugs enter the brain
neonatal and pediatric metabolism
- liver immature; does not produce enough microsomal enzymes
- older children may have increased metabolism, requiring higher doses than infants
neonatal and pediatric excretion
- kidney immaturity affects glomerular filtration rate and tubular secretion
- decreased perfusion rate of the kidneys may reduce excretion of drugs
Factors affecting pediatric drug dosages
- skin is thin and permeable
- stomach lacks acid to kill bacteria
- lungs have weaker mucus barriers
- body temperatures less well regulated, and dehydration occurs easily
- liver and kidneys are immature, impairing drug metabolism and excretion
Methods of dosage calculation for pediatric patients
- body surface area method
- always use weight in kilograms, not pounds
- always use centimeters, not inches
- body weight dosage calculations
Considerations for older adult patients
- older adults: older than age 65 years
- high use of medications
- polypharmacy
- noncompliance, nonadherence
- increased incidence of chronic illnesses
- sensory and motor deficits
Older adult Absorption
- gastric pH less acidic, gastric emptying slowed
- movement through GI tract slowed because of decreased muscle tone and activity
- blood flow to GI tract reduced
- absorptive surface of GI tract reduced
