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Introduction
Over
the years, far too many women have been wrongly
told they had to stop breastfeeding. The decision about
continuing breastfeeding when the mother takes a drug, for
example, is far more involved than whether the baby will get any
in the milk. It also involves taking into consideration the risks
of not breastfeeding, for the mother, the baby and the
family, as well as society. And there are plenty of risks in not
breastfeeding, so the question essentially boils down to: Does
the addition of a small amount of medication to the mother’s
milk make breastfeeding more hazardous than formula feeding?
The answer is almost
never. Breastfeeding with a little drug in the milk is
almost always safer. In other words, being careful means continuing breastfeeding, not stopping.
Remember
that stopping breastfeeding for a week may result in permanent
weaning since the baby may then not take the breast again. On
the other hand, it should be taken into consideration that some
babies may refuse to take the bottle completely, so that the
advice to stop is not only wrong, but often impractical as well.
On top of that it is easy to advise the mother to pump her milk
while the baby is not breastfeeding, but this is not always easy
in practice and the mother may end up painfully engorged.
Breastfeeding
and Maternal Medication
Most
drugs appear in the milk, but usually only in tiny amounts.
Although a very few drugs may still cause problems for infants
even in tiny doses, this is not the case for the vast majority. Nursing
mothers who are told they must stop breastfeeding because of a
certain drug should ask the physician to make sure of this by
checking with reliable sources.
Note that the
CPS (in Canada) and the PDR (in the USA) are not reliable
sources of information about drugs and breastfeeding.
Or the mother should ask the physician to prescribe an
alternate medication that is acceptable during breastfeeding.
In this day and age, it should not be a problem to find a safe
alternative. If the
prescribing physician is not flexible, the mother should seek
another opinion, but not
stop breastfeeding.
Why do most drugs appear in the milk in only small
amounts? Because what gets into the milk depends on the
concentration in the mother’s blood and the concentration in
the mother’s blood is often measured in micro- or even nano-grams
per millilitre (millionths or billionths of a gram), whereas the
mother takes the drug in milligrams (thousandths of grams) or
even grams. Furthermore, not all the drug in the mother’s
blood can get into the milk. Only the drug that is not attached
to protein in the mother’s blood can get into the milk. Many
drugs are almost completely attached to protein in the
mother’s blood. Thus, the baby is not
getting amounts of drug similar to the mother’s intake,
but almost always, much less on a weight basis. For example, in
one study with the antidepressant paroxetine (Paxil), the mother
got over 300 micrograms per kg per day, whereas the baby got
about 1 microgram per kg per day).
Most
drugs are safe if:
·
They
are commonly prescribed for infants. The
amount the baby would get through the milk is much
less than he would get if given directly.
·
They
are considered safe in pregnancy.
This is not always true, since during the pregnancy, the
mother’s body is helping the baby’s get rid of drug. Thus it
is theoretically possible that toxic accumulation of the drug
might occur during breastfeeding when it wouldn’t during
pregnancy (though this is probably rare). However, if the
concern is for the baby’s merely getting exposed
to a drug, say an antidepressant, then the baby is getting
exposed to much more drug at a more sensitive time during
pregnancy than during breastfeeding.
Recent studies about withdrawal symptoms in newborn
babies exposed to SSRI type antidepressants during pregnancy
somehow seems to implicate breastfeeding as if this type of
problem requires a mother not to breastfeed.
(Good example of how breastfeeding is blamed for
everything.) In
fact, you cannot prevent these withdrawal symptoms in the baby
by breastfeeding, because the baby gets so little in the milk..
·
They
are not absorbed from the stomach or intestines.
These include many, but not all, drugs given by injection.
Examples are gentamicin (and other drugs in this family of
antibiotics), heparin, interferon, local anaesthetics,
omperazole.
·
They
are not excreted into the milk. Some
drugs are just too big to get into the milk. Examples are
heparin, interferon, insulin, infliximab (Remicade), etanercept
(Enbrel).
The following are a few
commonly used drugs considered safe during breastfeeding:
·
Acetaminophen (Tylenol, Tempra), alcohol (in reasonable amounts), aspirin (in usual doses, for short
periods). Most antiepileptic medications, most antihypertensive
medications, tetracycline,
codeine, nonsteroidal antiinflammatory medications (such as
ibuprofin), prednisone, thyroxin, propylthiourocil
(PTU), warfarin,
tricyclic antidepressants, sertraline
(Zoloft), paroxetine (Paxil),
other antidepressants, metronidazole (Flagyl), omperazole (Losec),
Nix, Kwellada.
Note: Though
generally safe, fluoxetine (Prozac) has a very long half life
(stays in the body for a long time).
Thus, a baby born to a mother on this drug during the
pregnancy, will have large amounts in his body, and even the
small amount added during breastfeeding may result in
significant accumulation and side effects. These are rare, but
have happened. There are two options that you might consider:
1.
Stop the fluoxetine (Prozac) for the last 4 to 8 weeks of
your pregnancy. In this way, you will eliminate the drug from
your body and so will the baby. Once the baby is born, he will
be free of drug and the small amounts in the milk will not
usually cause problems and you can restart the fluoxetine
(Prozac).
2.
If it is not possible to stop fluoxetine (Prozac) during
your pregnancy, consider changing to another drug that does not
get into the milk in significant amounts once the baby is born.
Two good choices are sertraline (Zoloft) and paroxetine (Paxil).
·
Medications applied to the skin, inhaled (for example,
drugs for asthma) or applied to the eyes or nose are almost
always safe for breastfeeding.
·
Drugs for local or regional anaesthesia are not absorbed
from the baby’s stomach and are safe. Drugs for general
anaesthesia will get into the milk in only tiny amounts (like
all drugs) and are extremely unlikely to cause any effects on
your baby. They usually have very short half lives and are
eliminated extremely rapidly from your body. You can breastfeed
as soon as you are awake and up to it.
·
Immunizations given to the mother do not require her to
stop breastfeeding. On the contrary, the immunization will help
the baby develop immunity to that immunization, if
anything gets into the milk. In fact, most of the time
nothing does get into the milk, except, possibly some of the
live virus immunizations, such as German Measles. And that’s
good, not bad.
·
X-rays and scans. Ordinary X-rays do not require a mother
to stop breastfeeding even when used with contrast material (example, intravenous pyelogram). The reason is that
the material does not get into the milk, and even if it did it
would not be absorbed by the baby. The same is true for CT scans
and MRI scans. You do not
have to stop for even a second.
What
about radioactive scans?
We do not want babies to get radioactivity, but we rarely
hesitate to do radioactive scans on them. When a mother gets a
lung scan, or lymphangiogram with radioactive material, or a
bone scan, it is usually done with technetium (though other
materials are possible). Technetium
has a half life (the length of time it takes for ½ of all the
drug to leave the body) of 6 hours, which means that after 5
half lives it will be gone from the mother’s body. Thus, 30
hours after injection all of it will be gone and the mother can
nurse her baby without concern about his getting radiation. But
does all the radioactivity need be gone? After 12 hours, 75% of the
technetium is gone, and the concentration in the milk very low.
I think that waiting 2 half lives is enough, for a material such
as technetium. But:: Not all technetium scans require
stopping breastfeeding at all (HIDA scan, for example).
It depends on which molecule the technetium is attached
to. In the
first few days, there is very little milk (though there is
enough). In this
situation it would be unnecessary for the mother to stop
breastfeeding after a lung scan, for example.
However, one of the most common reasons to do a lung scan
is to diagnose a clot in the lung.
This can now be done better and faster with CT scan,
which does not require interrupting breastfeeding for even 1
second.
If you decide that interruption of breastfeeding is the
best course to follow, then express milk for several days in
advance (if you have advance warning about the test).
Only occasionally is a radioactive scan so urgent that it
cannot be delayed for a few days.
Thyroid scans are
different. Radioactive iodine (I¹³¹) is concentrated in milk
and will be ingested by the baby and it will go to his thyroid
where it will stay for a long time. This is definitely of
concern. So, the mother will have to stop breastfeeding? No,
because often the test does not need to be done at all.
Differentiating postpartum thyroiditis from Graves’ Disease
(the most common reason for doing the scan in nursing mothers)
does not require a thyroid scan. Get more information from the
clinic. If a scan
needs to be done, it is possible to do a thyroid scan I¹²³,
which requires stopping for only 12 to 24 hours, depending on
the dose given. Don’t
forget to express milk in advance so the baby can get it instead
of formula.
Questions?
(416) 813-5757 (option 3) or
drjacknewman@sympatico.ca
or my book
Dr. Jack Newman’s Guide to Breastfeeding (called The Ultimate Breastfeeding Book of Answers in the USA)
Handout
#9a. You Should Continue Breastfeeding (1) (Drugs and
Breastfeeding). Revised
January 2005
Written by Jack Newman, MD, FRCPC. © 2005
This
handout may be copied and distributed without further
permission,
on the condition that it
is not used in any context in which the WHO code on the
marketing of breastmilk substitutes is violated.
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