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Breastfeeding and drugs and breastmilk

As the number of nursing mothers continues to increase, so does the use of drugs, both legal and recreational. Here’s what you need to know about drugs and how they affect breastmilk.

Three things to know
As a nursing mother, you should be aware that there are three things we know for sure about drugs and breastmilk:

  • Nearly all drugs pass into human milk.
  • Almost all medication appears in very small amounts, usually less than 1 percent of the maternal dose.
  • Very few drugs are contraindicated for nursing mothers.

The issue of which drugs are safe to take during lactation is quite complicated. Many factors must be taken into consideration, such as:

The route of administration — Drugs can enter your system several different ways: orally, intravenously, intramuscularly, topically or through inhalation. Topical medications (skin creams) and medications inhaled or applied to the eyes or nose reach the milk in lesser amounts and more slowly than other routes and are almost always safe for nursing mothers. Oral medications take longer to get into the milk than IV and IM routes.

How often you take the drug — Medications taken 30 to 60 minutes before you feed are likely to be a peak blood levels when your baby nurses.

Your baby’s age and maturity level — The frequency and volume of feedings (the baby who is nursing once or twice a day, and is supplemented the rest of the time, will receive less of a drug than the baby who is totally breastfed and may nurse 10 to 12 times a day).

The type of medication — In the last decade or two, as breastfeeding rates have increased, so have the accuracy of the methods we use to measure drugs in human milk. This is good because in certain situations, such as nursing a very sick premature baby, knowing what medications appear in even very tiny amounts can be significant.

Many doctors are afraid to prescribe a drug because of the conservative approach taken toward giving drugs to a pregnant woman. They feel that if a drug might possibly cause birth defects in a pregnant woman, then they shouldn’t give it to a lactating woman. The difference is that while the placenta lets drugs enter to cross into the developing fetus’ bloodstream, the breast serves as a very effective barrier for a fully developed infant.

Doctors tend to err on the side of caution and recommend that a mother wean rather that do research and reassure the mother that the medication is safe for her baby (as the majority of drugs are), or explore alternative, safer medications. You should be aware that the PDR (Physician’s Desk Reference — also known as the doctor’s bible) contains very little information about breastfeeding, and bases its recommendations on the idea that no drug should be taken by a nursing mother unless it has been proven absolutely safe in all circumstances.

The problem with that is that there is virtually no drug in the world, including Tylenol, that can be said to be absolutely safe all the time. In deciding which drug to take, you should always look at the situation from a risk/benefit perspective: The benefits of breastfeeding are well known and undisputed, so doctors should recommend a mother wean only when there is scientific documentation that a drug will be harmful to her infant. A doctor who believes in the value of breastfeeding should take the time to explore alternative therapies, or if nursing must be interrupted, encourage the mother to continue pumping her milk to maintain her supply and return to breastfeeding as soon as possible. If your doctor prescribes a drug which he says in incompatible with breastfeeding, it is reasonable to ask for documentation and/or alternative medications.

General guidelines for taking drugs while nursing

  • Only take a medication if you REALLY need it. Consider alternative, non-drug therapies if possible.
  • If you have a choice, delay starting the drug until the baby is older. A drug which might cause problems for a newborn may be fine for an older, larger, more mature infant.
  • Take the lowest possible dose for the shortest possible time.
  • Schedule the doses so that the lowest amount gets into the milk (take it soon after a feeding, preferably a night feeding, rather than right before nursing).
  • Watch for reactions such as sleepiness, rashes, diarrhea, colic, etc. Although reactions are rare, it is important to keep your doctor informed of any changes.
  • If you must take a drug that is contraindicated, and no alternatives are available, get a good electric pump to maintain your milk supply if you need to wean for more than a day or two. Your supply will build up when the baby starts nursing again.

Some very general information about drugs that are usually considered safe to take during breastfeeding follows:

If the drug is commonly prescribed for infants, it is most often safe to take while nursing, because the baby generally gets a much lower dose from the milk than he would from taking it directly. Examples are most antibiotics, such as amoxycillin.

Drugs considered safe during pregnancy are usually, but with a few exceptions, safe to take while nursing.

Drugs that are not absorbed from the GI tract (stomach or intestines) are usually safe. Many of these drugs are injected, such as heparin, insulin, lidocaine or other local anesthetics. Immunizations such as German measles, flu shots, TB tests, or Hepatitis A and B, are not harmful to the baby — even the ones with live viruses.

Most antiepileptic medications, antihypertensive medications and nonsteroidal antinflammatory medications are safe during lactation. Antidepressant medications and their use by nursing mothers are being extensively studied, as more and more women are currently being treated for depression, which often occurs during the postpartum period. Some studies suggest that the one-year old infants of mothers who are depressed may not exhibit normal neurobehaviorial development. It is therefore important to treat depression and also to continue breastfeeding during treatment, because one of the many benefits of breastfeeding is its positive effect on neurodevelopment.

Use of antidepressant medication does not normally contraindicate breastfeeding. We do have more information about the safety of some medications than we do about others. Currently, he most widely prescribed antidepressants are SSRI (seretonin-selective reuptake inhibitors) such as Paxil and Zoloft. Both appear in mother’s milk in very small amounts. Zoloft is the preferred antidepressant for nursing mothers because it is effective for many mothers, and studies on breastfed babies show that their blood levels are usually too low to be measured. It is usually the first medication to try.

Paxil is usually considered safe for nursing mothers. It seems to get into the milk in very minimal amounts. Prozac is not the drug of choice because it has a longer half-life and more appears in milk that the other SSRI medications. Prozac should be avoided in the mother is nursing a premature or newborn infant, especially if she took the medication during her pregnancy. Treatment with Prozac is less likely to cause problems if the baby is four to six months old because the baby is better able to eliminate it when he is older.

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