Can I Take ______ While Breastfeeding?

I frequently get calls and emails from mothers wondering if a certain medication is compatible with breastfeeding. I have a fantastic reference I consult called Medications and Mothers’ Milk by Thomas W. Hale, which lets me know which lactation category a drug falls in, what the categories mean, and other information including the molecular weight of a medication, its oral bioavailability, protein binding and how long the medication will remain in the mother’s body. For some medications an alternative drug will be suggested and moms can then decide with their physicians which medication is most suitable for their particular situation.

Many more medications are compatible with breastfeeding than with pregnancy, but just because a medication is safe in pregnancy, does not necessarily imply that it is safe for breastfeeding and vice versa. The main reason for the difference is that in pregnancy, moms and babies share almost everything in their bloodstreams via the placenta. Oxygen, nutrients, medications and anything else in the mother’s bloodstream is shared more or less unfiltered with her baby. Any waste products in the babies bloodstream are also shared with the mother, whose mature liver and kidneys can do the work of getting rid of them for the baby.

In breastfeeding, milk is created by special cells in the breasts. These cells collect nutrients from the mother’s bloodstream, but also act as a filter. Any medication in the mother’s bloodstream that is very large, or bound strongly to protein, will not pass very readily into the milk. Many medications also have low oral bioavailability, meaning that taken by mouth they do not travel readily to the bloodstream so are unlikely to be found in high quantities in breastmilk, or to affect a baby. If, however, a substance or medication does pass readily into the baby’s system through the breastmilk, it is then up to the baby’s liver and kidneys to process it. This is the main reason that some drugs are considered safer during pregnancy than during breastfeeding.

Below is a very short list of some common medications and substances that fall into the various lactation categories. You will see that the majority are considered compatible with breastfeeding.

Lactation Category 1: “Safest. Drug which has been taken by a large number of breastfeeding mothers without any observed increase in adverse effects in the infant. Controlled studies in breastfeeding women fail to demonstrate a risk to the infant and the possibility of harm to the breastfeeding infant is remote; or the product is not orally bioavailable in an infant.”


  • acetaminophen (Tylonol)
  • albuterol
  • allergy injections
  • ibuprofen (Advil, Motrin)
  • levothyroxin
  • loratadine (Claritin)
  • domperidone (Motilium)
  • insulin

Lactation Category 2: “Safer. Drug which has been studied in a limited number of breastfeeding women without an increase in adverse effects in the infant. And/or, the evidence of a demonstrated risk which is likely to follow use of this medication in a breastfeeding woman is remote.”


  • cetirizine (Zyrtec)
  • diphenhydramine (Benadryl)
  • caffeine
  • omeprazole (Prilosec)
  • ranitidine (Zantac)
  • guaifenesin (Robitussin)
  • sertraline (Zoloft)
  • paroxetine (Paxil)
  • fluoxetine (Prozac)

Lactation Category 3: “Moderately Safe. There are no controlled studies in breastfeeding women; however, the risk of untoward effects to a breastfed infant is possible, or controlled studies show only minimal non-threatening adverse effects. Drugs should be given only if the potential benefit justifies the potential risk to the infant. (New medications that have absolutely no published data are automatically categorized in this category, regardless of how safe they may be.)”


  • chlorpheniramine (Chlor-Trimeton)
  • codeine
  • echinacea
  • fenugreek
  • garlic
  • gentian violet
  • lansoprazole (Prevacid)
  • aspirin
  • oral contraceptives - milk supply concerns

Lactation Category 4: “Possibly Hazardous. There is positive evidence of risk to a breastfed infant or to breastmilk production, but the benefits from use in breastfeeding mothers may be acceptable despite the risk to the infant (e.g., if the drug is needed in a life-threatening situation or for a serious disease for which safer drugs cannot be used or are ineffective.)”


  • pseudoephedrine (Sudafed) - milk supply concerns
  • fennel

Lactation Category 5: “Contraindicated. Studies in breastfeeding mothers have demonstrated that there is significant and documented risk to the infant based on human experience, or it is a medication that has a high risk of causing significant damage to an infant. The risk of using the drug in breastfeeding women clearly outweighs any possible benefit from breastfeeding. The drug is contraindicated in women who are breastfeeding an infant.”


  • antineoplastic agents (chemo therapy)
  • kombucha tea
  • isotretinoin (Accutane)
  • cannabis
  • cocaine
  • heroin
  • LSD

One point I think is worth mentioning is that sometimes if a mother needs to take one of the few drugs that is not compatible with breastfeeding, she may hesitate because her nursing relationship with her baby is so dear to her. In such a case I would recommend to the mother that she have an open conversation with her health care provider about how important her breastfeeding relationship is, and ask if there are other medications that might be safer she could try instead. Sometimes though, such as with many cancer treatments, there will be no safe alternative, and in a case like this, I would advise the mother to take the long view of the situation. She will certainly miss and grieve her nursing relationship, and weaning, especially if it needs to be done abruptly may be hard for both mother and child. However, being around to parent her child in the future is worth it, even if weaning will be extremely sad.

If you have questions about a medication you are taking or need to take, many La Leche League Leaders and most lactation consultants have copies of Medications and Mothers’ Milk and can read you the section about the medication. Most of the time, it is reassuring for mothers to learn that the medication is compatible with breastfeeding (as most are!). Kellymom and BabyCenter also have listings of medications and lactation categories.

These lists are for general information only. I urge you to get as much information as you can before using any medications during lactation, since most medications do pass into your milk to some degree. Please double check the information given here with the original references before using it to make any decisions.

* All material in this article (and on this website) is provided for educational purposes only, although every effort is made to provide accurate and up-to-date information. This article and others on this website are not written by doctors or other health care professionals. If you are concerned about your health, or that of your child, consult with your health care provider regarding the advisability of any opinions or recommendations with respect to your individual situation.