Lecture 11 - Dec 2

Question 1

-read Rh and Hep B for exam

Question 2

menti https://www.menti.com/alhcthccnpis

Question 3

slide 5

Question 4

slide 6

Question 5

slide 7

Question 6

metabolism in pregnancy

Answer 6

-in general most drugs are cleared by CYP1A2 which is decreased, so drugs are metabolised slower, also decreased blood flow to liver due to uteroplacenatal circulation
-so drugs metabolized by liver are cleared slower in pregnancy
-though some enzymes like CYP3A6 are increased

Question 7

slide 9

Question 8

placental transfer of drugs

Answer 8

-in general, transfer across placenta follows same kinetics as any other tissue
-can transfer antibodies drugs, hormones, nutrients, oxygen, pathogens/viruses, vitamins, water
-easily transfer: lipid soluble/non-ionized, low molecular weight, low protein binding in the parturients plasma

Question 9

Drugs can cross placenta by:

Answer 9

-passive diffusion: oxygen, carbon dioxide, fatty acids, steroids, electrodes, fat-soluble vitamins, drugs
-facilitated diffusion: sugars
-solvent drag: electrolytes (bulk flow, paracellular (passing through the intercellular space between cells in the epithelium - passive diffusion process)
-active transport: amino acids, some cations (calcium, iron, iodine, phosphate), water soluble vitamins
-most drugs cross placenta by diffusion

Question 10

factors affecting placenta transfer

Answer 10

-surface area of the placenta and diffusing distance
-physiochemical properties of drugs - lipid solubility, moceluclar weight (most drugs above 1000Da will not cross placenta), degree of ionization (pH), protein binding
-concentration gradients

Question 11

slide 13

Answer 11

-placenta starts to thin/flatten (but also as it grows throughout pregnancy it has more vessels for diffusion) as baby gets bigger so distance that things need to diffuse across gets smaller

Question 12

Maternal metabolites can also cross placenta