Midterm Exam Study Guide
Risk categories:
■X
● Clear evidence of fetal harm
● Risks ALWAYS OUTWEIGH BENEFITS
● ABSOLUTE CONTRAINDICATION: Category X drugs should
never be used in pregnancy
Risk Category X Drugs you MUST know COLD
○ Isotretinoin
○ Thalidomide
○ Warfarin
○ Methotrexate
○ Misoprostol
Risk-Benefit Analysis in Prescribing
When prescribing during pregnancy, the APRN must evaluate severity of maternal condition,
consequences of UNTREATED DISEASE, gestational age, known fetal risks of the drug, and availability of
safer alternatives.
Untreated Maternal Disease
Untreated maternal disease can be MORE DANGEROUS THAN DRUG EXPOSURE
Safest Effective Option in Prescribing
Prescribing principles include choosing the LOWEST RISK CATEGORY drug when possible, using the
LOWEST EFFECTIVE DOSE, avoiding unnecessary combination therapy, avoiding drugs with known
teratogenic effects, and preferring drugs with established safety data in pregnancy.
Safest Effective Therapy
Recognize that 'safest effective therapy' does not mean no therapy.
Age-Related Pharmacokinetic Changes - Geriatrics
■ ↓ renal clearance
■ ↓ hepatic metabolism
■ ↑ drug sensitivity
Prescribing for elderly populations
○ Start low, go slow
○ Monitor closely
○ Minimize polypharmacy
, Pharmacokinetics in elderly and infants
In general IV meds → no absorption occurs
○ Pharmacokinetics in Infants
■ Absorption
● Gastric pH is higher (less acidic)
● Gastric emptying is delayed and variable
● Oral absorption is UNPREDICTABLE
● Testable points!!!!
○ infant absorption is VARIABLE, not absent
○ Pharmacokinetics in Infants
■ Distribution
● ↑ total body water
● ↓ body fat
● ↓ plasma protein binding
● Testable points!!!!!
○ Water-soluble drugs require higher mg/kg doses
○ ↓ protein binding → ↑ free drug → toxicity risk
○ Pharmacokinetics in Infants
■ Metabolism
● Hepatic enzyme systems are immature at birth
● Metabolic capacity increases over time
● Testable point!!!!!
○ Immature liver → ↓ metabolism → ↑ half-life
○ Pharmacokinetics in Infants
■ Excretion
● Immature kidneys
● ↓ glomerular filtration rate
● ↓ tubular secretion and reabsorption
● Testable point!!!!
RENAL IMMATURITY IS A MAJOR CAUSE OF INFANT DRUG TOXICITY
○ Pharmacokinetics in Infants
■ Half-Life
● Prolonged due to ↓ metabolism and ↓ excretion
● Increased risk for accumulation
○ Pharmacokinetics in Pediatrics
■ Pediatric pharmacokinetics CHANGE WITH AGE and do NOT EQUAL ADULT PK
■ Hepatic function improves at age 1