Question

GP08 [Jul98] [Jul01] [Mar02] Which statemnent is NOT true re placental transfer of drugs:

A. Increases in late pregnancy
B. Increases late because of decreased albumin
C. Do not cross if MW > 600 daltons
D. Lipid soluble drugs diffuse through placenta depending on concentration gradient
E. Increased diffusion if greater plasma protein binding in fetus

Answer 1

The false statement about placental drug transfer is that increased diffusion occurs with greater fetal plasma protein binding; in fact, protein binding reduces free drug availability for transfer.

Step-by-step explanation:

The statement that is NOT true regarding placental transfer of drugs is: E. Increased diffusion if greater plasma protein binding in fetus. This is because plasma protein binding reduces the quantity of free drug available for transfer. The placenta facilitates the transfer of various substances, including nutrients and oxygen from the maternal blood to the fetus, and waste from the fetal blood to the mother. Drugs can cross the placenta if they are lipid-soluble; they diffuse through depending on concentration gradient, and most drugs do cross the placenta unless their molecular weight (MW) is particularly high, typically greater than 600 Daltons. Albumin levels may affect the amount of free drug available for transfer; lower albumin can result in higher free drug concentrations, which can then cross the placenta more readily.