Pregnancy and Lactation Pharmacokinetics Flashcards
What are the hemodynamic changes experienced in pregnancy?
- increased cardiac output
- increased blood volume
- decreased blood pressure
What are the GI tract changes that effect absorption in pregnancy?
- increased gastric emptying time
- increased gastric pH
- decreased GI motility
- decreased gastric acid secretion
How is drug distribution effected by increased total body water?
increased Vd (particularly for hydrophilic drugs) and decreased Cmax concentrations
How is drug distribution effected by increased fat stores?
increased Vd (drugs with binding affinity for fat tissue)
How is protein binding effected by pregnancy?
plasma volume expands more than albumin production causing dilutional hypoalbuminemia= decreased protein binding to albumin= increased fraction unbound= more free rug avaliable to bind to receptors and to be eliminated
What drug characteristics are effected by the increased hepatic blood flow?
high ER drugs experience increased clearance
What renal parameters are increased during pregnancy?
- renal blood flow
- GFR and CrCl
- activity of renal tubular P-gp and OAT/OCT transporters
What renal parameters are decreased during pregnancy?
- serum creatinine
- BUN
- steady state plasma drug concentrations and half-life
How do substances enter the placenta?
passive diffusion
concentration gradient dependent
What characteristics of drugs can move into the placenta?
low molecular weight substances, and as drug size increases lipid solubility and ionization become more important to determine drug movement
concentration gradient dependent
What are the physiochemical drug factors that affect drug movement into breast milk?
- degree of drug ionization
- drug size
- lipid solubility
- degree of protein binding
How do drugs enter the breast milk?
passive diffusion or active transport
What drug characteristics typically enter the mothers breast milk?
- weak bases
- lipid soluble
- poorly protein bound
