Pregnanacy

Question 1

Two thirds of pregnant patients take at least

Answer 1

one medication;

Question 2

most pregos take medication for

Answer 2

For pregnancy-related problems such as nausea, constipation, and
preeclampsia
 For chronic disorders such as hypertension, diabetes, and epilepsy
 For infectious diseases or cancer
 Drugs of abuse such as alcohol, cocaine, and heroin

Question 3

With enough time and high concentrations most drugs will

Answer 3

cross the placenta.

Question 4

The physiological changes of pregnancy have an

Answer 4

affect on the pharmacokinetics

of drugs.

Question 5

The determinants of transfer across the

Answer 5

placenta and breast tissue are the same.

Question 6

MATERNAL PHYSIOLOGICAL CHANGES OF PREGNANCY WHICH IMPACT DRUG
PHARMACOKINETICS - absorption

Answer 6

Delay in gastric emptying time
 Decrease in intestinal motility
 Increased gastric pH

Question 7

MATERNAL PHYSIOLOGICAL CHANGES OF PREGNANCY WHICH IMPACT DRUG
PHARMACOKINETICS - volueme of distribution

Answer 7

Plasma volume increases by 50 %
 Plasma volume increases by 80% in multiple gestations
 Plasma volume has an additional increase of 20-50% with use of beta-adrenergic tocolytic
agents
 8L increase in total body water (maternal 40%, fetus/amniotic: 60%)

Question 8

MATERNAL PHYSIOLOGICAL CHANGES OF PREGNANCY WHICH IMPACT DRUG
PHARMACOKINETICS AND PHARMACODY - protein changes

Answer 8

Serum albumin levels fall resulting in decreased availability of protein-binding sites for acidic
drugs and increased free drug serum concentration (e.g. salicylic acid, sulfisoxazole,
diazepam, valproic acid,).

Question 9

MATERNAL PHYSIOLOGICAL CHANGES OF PREGNANCY WHICH IMPACT DRUG
PHARMACOKINETICS AND PHARMACODY - hepatic volume

Answer 9

Variable changes in rate of metabolism of drugs
 Enhance some (phenytoin)
 Inhibit others (theophylline)
 Excretion of drugs into biliary system may slow

Question 10

MATERNAL PHYSIOLOGICAL CHANGES OF PREGNANCY WHICH IMPACT DRUG
PHARMACOKINETICS AND PHARMACODYNAMICS - Renal Clearance

Answer 10

Increased renal blood flow 20-50%

 Increase in glomerular filtration rate by 50%

Question 11

MATERNAL PHYSIOLOGICAL CHANGES OF PREGNANCY WHICH IMPACT DRUG
PHARMACOKINETICS AND PHARMACODYNAMICS Pre-Eclampsia

Answer 11

Decrease in volume of distribution
 Decrease in glomerular filtration rate
 Decrease in hepatic metabolism rate

Question 12

Placenta

Answer 12

Organ of exchange

 Functions fully by 5th week after conception

Question 13

FACTORS AFFECTING TRANSFER - materanl

Answer 13

 Dose
 Rate and Route of administration
 Maternal pharmacokinetics
 Maternal plasma protein-binding capacity
 Uterine contraction/timing of IV infusio

Question 14

FACTORS AFFECTING TRANSFER - drug characteristics

Answer 14

 High lipophilicity
 Low ionization
 Low molecular weight
 Low protein-binding capacit
 Pharmacological activity of metabolites
 pH of the tissue or solution

Question 15

FACTORS AFFECTING TRANSFER - fetal

Answer 15

Fetal circulation and hepatic accumulation
 Placental enzymatic activity
 Reverse placental transfer
 PH of the fetal blood

Question 16

FICK PRINCIPLE

Answer 16

Q = KA(Cm – Cf)
t D
Q/t = rate of diffusion
A = placental surface available for transfer
Cm = free drug concentration in maternal plasma
Cf = free drug concentration in fetal blood
D = membrane thickness
K = diffusion constant for any specific drug