The Game of Medication Telephone
A few weeks ago, I wrote a Facebook post about the game of “Medication Telephone” and how it relates to breastfeeding. This is an area of medicine and lactation that I am passionate about, because it is overwhelmingly misunderstood from patient to healthcare provider. “Medication Telephone” is one of the reasons healthcare providers continue to give poor recommendations regarding maternal medication and breastfeeding.
A prescription medication, over-the-counter (OTC) medication, herbal supplement, dietary supplement, etc. takes a long and complicated path before it reaches the breastmilk and transfers to the baby. There are many factors to consider when determining if a medication is safe for the lactating individual, baby, and supply. “Medication Telephone” is the first concept to understand before critically thinking about whether or not a lactating individual can take a medication.
I like to call this concept “Medication Telephone,” because I think most of us remember the game of “Telephone” from when we are younger. For those who are not familiar, “Telephone” is a game where one person comes up with a sentence or saying and whispers it to the next person. This continues until it reaches the last person, and this person says the phrase out loud so everyone can hear. Typically, the sentence or saying is completely different than the original, because it has been broken down or transformed throughout the line of people. The same is true for medications. The lactating individual’s body breaks down or transforms the medication in some way before it ever reaches the breastmilk. it goes through further changes and transformations once the baby ingests the breastmilk. So, let’s discuss this long and complicated path from the lactating individual to the baby. I’ll use Zoloft (generic name is sertraline) as an example, since it has been extensively studied in lactating individuals. It’s also a medication I’m asked about frequently, and most people have heard of it.
When a lactating individual ingests Zoloft, the breakdown of Zoloft begins in the mouth. Saliva comes in contact with Zoloft and begins to digest it. Medications typically spend a very short amount of time in the mouth so breakdown is minimal, but some medications dissolve in the mouth and rapidly enter the bloodstream. Zoloft then travels to the digestive tract. Multiple factors determine if a medication is broken down and absorbed into the bloodstream from the stomach, small intestine, or large intestine. At some point the medication is absorbed from the digestive tract or it is eliminated without being absorbed. This is important - at least some medication is lost at this step.
After Zoloft enters the bloodstream, it goes to the liver and undergoes a process called “first pass metabolism.” First pass metabolism is where your liver breaks down or transforms a medication before it travels anywhere else in the body. In some cases, medications are “extensively metabolized,” which means they are significantly broken down and then eliminated. This is another important point - your liver will break down at least some of the medication before it is able to exert its clinical effect, let alone travel to the baby and exert its clinical effects.
Now that it has been at least somewhat broken down or transformed, Zoloft is available in the bloodstream and at other locations of the body. There are factors that I won’t get into during this post that can postpone or prevent Zoloft from making it to the milk-making cells, including elimination by the kidneys. Here is an important point - not all free medication (the form of medication able to exert its clinical effect) will make its way to the milk-making cells.
So, at least some Zoloft makes its way to the breasts and the milk-making cells. The milk-making cells are selective about what’s allowed to pass through them and into breastmilk. A medication has to be fat soluble enough to cross through the cells and water soluble enough to stay in the breastmilk. The medication is also picky, so sometimes it doesn’t want to transfer to milk. Or sometimes the medication transfers freely but doesn’t want to stay. This is important - you have to understand the properties of the medication to know if it will transfer AND concentrate in the breastmilk.
FINALLY. Zoloft has transferred to the breastmilk. What happens next? The baby transfers the breastmilk with Zoloft in it, and the whole process - from mouth to digestive tract to liver to bloodstream - happens again. The same opportunities for medication loss and breakdown occur. After this long journey, only a very small amount of Zoloft is transferred to baby and available to exert any effect in the baby. In fact, studies have shown that levels of Zoloft are undetectable in babies if under a certain dose. Zoloft went through “medication telephone” and ended up as a tiny crumb of the three-tiered wedding cake it was originally.
This is the general process for an oral medication. Other formulations (topical, intramuscular, subcutaneous, intravenous, intranasal, etc.) have slightly different paths and factors to consider. Individual consideration of a medication or class of medication is necessary.
So, the TAKEAWAY: medications take a long and complicated path before they ever reach the baby. Many are broken down and eliminated either by the lactating individual or the baby before they can have a clinical effect in the baby. It is important to consider each medication or class of medication individually. The concept of “medication telephone” is why many maternal medications are safe for the baby.
1) Dr. Thomas Hale: Medications and Mother’s Milk
2) American Society of Health-Systems Pharmacists (ASHP): Introduction to Pharmacokinetics and Pharmacodynamics
3) Rasmussen F. The mechanisms of drug secretion into milk (abstract)
4) The American Academy of Pediatrics (AAP): Transfer of Drugs and Therapeutics Into Human Breast Milk: An Update on Selected Topics
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