EMP 194
Special Considerations in Drug Therapy
Pregnancy and Lactation
Pregnancy presents 2 pharmacological problems.
Problem #1
Pregnancy causes a number of
anatomical and physiological changes in the mother. These changes must be considered when
administering medications to anyone who is pregnant. The anatomical and physiological changes to
be considered are as follows:
Ø
Mother’s Cardiac
Output is increased
Ø
Mother’s resting
heart rate is increased
Ø
Mother’s blood
volume increases by as much as 45%
Ø
Mother also has
decreased protein binding capabilities that hinders the pharmacokinetics and
pharmacodynamics of certain medications
Ø
Mother’ hepatic
metabolism is decreased. This means that
many drugs that require biotransformation in the liver will not be as
efficient.
Ø
Mother’s blood
pressure normally decreases
Problem #2
Medications administered to
the mother have the potential to cross the placenta and affect the fetus or can
affect a breast-feeding infant because many medications are excreted readily
into the breast milk. The US Food and
Drug Administration categorizes, most drugs based on their safety in pregnancy
(see table below). You must take the
time to memorize these FDA pregnancy categories.
|
Category |
Description |
|
A |
Adequate studies in pregnant women have not
demonstrated a risk to the fetus in the any trimester. This medication is safe to administer
during pregnancy or while breast feeding. (Class 1) |
|
B |
1.) Animal studies have not demonstrated a risk to
the fetus, but no adequate studies in pregnant women. This medication is
probably safe to administer during pregnancy or while breast feeding. (Class
2a) - OR - 2.) Adequate studies in pregnant women have not
demonstrated a risk to the fetus in any trimester, but animal studies have
demonstrated a risk of possible adverse effects. This medication is probably safe to
administer during pregnancy or while breast feeding. (Class 2a) |
|
C |
1.) Animal studies have demonstrated adverse
effects, but there are no adequate studies in pregnant women; however,
benefits may be acceptable despite the potential risk. (Class 2b) - OR - 2.) No adequate animal studies or adequate studies
of pregnant women have been done on this medication. (Class 2b) |
|
D |
Fetal risk has been demonstrated. In certain circumstances, benefit could
outweigh the risks. (Class 2b) |
|
X |
Fetal risk has been demonstrated. This risk outweighs any possible benefit to
the mother. AVOID using in pregnant, potentially pregnant, or mothers who are
breast feeding.(Class 3) |
Note: Class 1 =
defiantly helpful, Class 2a = probably helpful,
Class 2b = possibly helpful, Class 3 = not helpful