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Medications and Breastfeeding

Sara Walters
Carmarthen Wales UK
From NEW BEGINNINGS, Vol. 25, No. 2, 2008, pp. 32-33

Like everyone else, breastfeeding mothers can become ill or be living with a chronic condition that requires treatment. As a breastfeeding mother, you may feel concerned as to whether or not it is safe to take a particular medication. Perhaps you wonder if the medication will pass through your milk to your baby, or maybe it has been suggested that weaning is the only option if you are to get better. How does a breastfeeding mother know if a medication is safe?

Most Medications Are Safe

In the vast majority of cases, prescription and over-the-counter medications are compatible with breastfeeding. Even though most will pass into a mother's milk, it is usually in very small quantities. But because every situation is unique, it is important to gather information about a medication and work closely with your health care provider, particularly if there is any uncertainty about a medication's suitability for you or your breastfed baby.

Many health care providers may err on the side of caution when prescribing a medication for a breastfeeding mother. Some use resources such as The Physicians' Desk Reference (PDR), which takes a rather conservative view regarding safety, as the majority of the information is provided by drug companies that are concerned about lawsuits. If your doctor says the medication he/she is prescribing isn't compatible with breastfeeding and that you need to wean, it is worthwhile asking which resources he or she is using.

Fortunately, there is information available that provides a more objective view on medications and breastfeeding. For example, Dr. Thomas Hale's Medications and Mothers' Milk is a professional book that contains reviews of the scientific literature regarding a vast range of medications (categorized by safety), and provides alternatives if there are known concerns regarding a particular drug.

Working With Your Doctor

It is always important to tell your health care provider that you are breastfeeding, whether your child is a newborn, a six-month-old baby, or a nursing toddler. Many doctors may assume that an older baby has weaned. If your doctor recommends a drug but says it isn't compatible with breastfeeding, explain to him or her that breastfeeding is important to you and that you do not want to stop. Ask if there are alternatives, or even if medication is really necessary. Clearly there's a world of difference between treating a minor ailment and a life-threatening condition. Also, ask the doctor to do more research on the medication. Further investigation may reassure your doctor that a medication is indeed safe for breastfeeding mothers to use. Or your doctor may find that another medication is safe. Your feelings about continuing to breastfeed are important, too.

Questions to Consider

There are four main questions to ask when considering medications while breastfeeding:

  1. Will the drug affect my baby?
  2. Will the drug affect lactation?
  3. What are the risks of weaning?
  4. What are the options?

In order to answer these questions, more specific information is needed:

  1. Does the drug pass into the milk? How much of the mother's dose appears in the milk?
  2. If the drug does pass into the milk, how much is absorbed by the baby? Some drugs are not absorbed into the bloodstream from the digestive­ tract. Others are poorly absorbed, making them safer for breastfeeding.
  3. How old is the baby? How big is the baby? The older the baby, the better he is able to eliminate the drug from his system. A baby who weighs more may be less affected by a drug than a smaller baby of the same age. Some drugs that would be harmful to a breastfeeding­ newborn or premature baby may not a problem for a breastfeeding toddler.
  4. How much milk is the baby getting? A baby who is eating lots of solid food would probably be less exposed to the drug than a baby who is still exclusively breastfeeding.
  5. Is the drug used to treat babies? Generally a medication that can be given directly to babies is a good choice for a breastfeeding mother, although this may not apply to premature babies.
  6. How long has the medication been available? There may be more information available about a time-tested drug and the effects on breastfeeding than about a new product.
  7. What is the drug's half-life? Is it short-acting or long-acting? A short half-life and a short-acting­ drug are preferable for breastfeeding mothers. These drugs are less likely to accumulate­ in the milk or in the baby.
  8. How long does the drug need to be taken? Sometimes a medication that is taken for several weeks or even months is more likely to affect a baby than one taken for just a few days.
  9. How is the drug taken? One that is injected directly into the bloodstream will have more impact than one given topically or orally.
  10. What is the dosage of the drug?
  11. How well does the baby's body break down and excrete the drug? One that accumulates in the baby's system is of more concern than one that is quickly eliminated.
  12. Does the drug affect milk production?
  13. What are the characteristics of the drug? For example, alkaline drugs pass more easily into milk than acidic ones. Fat-soluble drugs pass more quickly into milk than water-soluble ones. Drugs with large molecules may be too large to pass into the milk, and drugs with proteins that bind may have fewer molecules floating into the milk. Your doctor may want to talk with a pharmacologist to better determine­ whether a drug is likely to enter a mother's milk in significant amounts.

In short, the preferred medication for a breastfeeding mother would be one that is:

  1. Least toxic to the baby.
  2. Has a short half-life.
  3. Is least concentrated in mother's milk.
  4. Time-tested.
  5. Given in the smallest effective dose for the shortest course.

Tips to Reduce Your Baby's Exposure to Medication

If you are concerned about the effect your medication may have on your baby, even if you have been given the go-ahead to take it, there are a couple of things you can do to minimize exposure. For example, it is often best to take the drug right after breastfeeding, so it has time to clear from your system before you nurse again. Also taking medication before your baby's longest sleep period may be a good idea. However, different medications are absorbed and eliminated at different rates. Ask your doctor for more information.

Of course, no drug is completely safe for everyone, as everyone reacts differently to a medication. Individual circumstances, such as diet or other medications you are taking, can affect how you react to a particular drug. These are all things your health care provider will take into consideration when prescribing a medication. But weaning is seldom necessary when a breastfeeding mother needs to take a medication.

If you do need to take medication while you are nursing your baby and your doctor says it's okay to do so, try not to agonize about it. If you are concerned, find out the reasons why it is considered compatible with breastfeeding so you can feel more confident in the recommendation. Take the medication as directed so that you can be a happy, healthy mother to your baby.

Information in this article is based on guidelines given in THE BREASTFEEDING ANSWER BOOK POCKET GUIDE, by Nancy Mohrbacher (LLLI 2005). For more information see:
Hale, T. Medications and Mothers' Milk. Amarillo, TX: Hale Publishing, 2006.
Mohrbacher, N. and Stock, J. The Breastfeeding Answer Book. Schaumburg, IL: LLLI, 2003.
Mohrbacher, N. The Breastfeeding Answer Book Pocket Guide. Schaumburg, IL: LLLI, 2005.

Note: Although La Leche League Leaders can share resources with information about the safety of medications for breastfeeding mothers, they are not health professionals and cannot offer an opinion about whether a mother should take medication. Nor can they recommend a particular medication. If you need more information about a specific medication, please contact a Leader with the name of the drug in question. She will share with you, verbatim, what her resource tells her about that medication. To find an LLL Leader in your area, go to

This article was adapted from the column, "I Need to Know," which appears in LLL GB Breastfeeding Matters.

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