Cough and Allergy Medications During Lactation: Safe Choices to Avoid Infant Sedation

When you're breastfeeding and hit with a bad cold or seasonal allergies, the last thing you want is to choose between feeling better and keeping your baby safe. Many common cough and allergy medications seem harmless-until you learn how they can make your baby dangerously sleepy. The truth is, not all meds are created equal when it comes to breastfeeding. Some pass into breast milk in tiny amounts and are fine. Others, like codeine and diphenhydramine, can cause serious sedation, slow breathing, or even feeding problems in newborns. Knowing which ones to avoid-and which ones are truly safe-can make all the difference.

Why Some Medications Make Babies Sleepy

Not all drugs cross into breast milk the same way. What matters most is how much gets through, how long it stays in the baby’s system, and how their tiny body handles it. Newborns, especially under two months, have underdeveloped livers and kidneys. They can’t break down or flush out certain drugs like adults can. That’s why even small amounts of sedating medications can build up and cause problems.

The biggest culprits are first-generation antihistamines like diphenhydramine (Benadryl) and chlorpheniramine. These are designed to cross the blood-brain barrier to block allergy symptoms-and that same ability lets them enter the baby’s brain. Studies show about 1.6% of nursing infants become noticeably drowsy after maternal use. It’s not common, but when it happens, it’s serious. Babies may sleep through feedings, have trouble latching, or show shallow breathing. One mother on a breastfeeding forum reported her 6-week-old became so sleepy he missed three straight feeds after she took one Benadryl. The ER confirmed it was likely medication-related.

Codeine is even more dangerous. Once commonly prescribed for postpartum pain and cough, it’s now known to be metabolized differently in some people. About 1 in 100 Caucasian mothers are ultra-rapid metabolizers, meaning their bodies turn codeine into morphine much faster than normal. That morphine then passes into breast milk at levels up to 20 times higher than expected. In 2017, the FDA issued a black box warning-the strongest possible-for codeine use during breastfeeding. There are documented cases of infant deaths linked to this. A 13-day-old baby died after his mother took codeine for pain. The risk isn’t theoretical. It’s real, and it’s deadly.

What’s Actually Safe to Take

The good news? You don’t have to suffer through allergies or a cough without relief. Several medications are considered safe and effective during breastfeeding, with minimal transfer to milk and no reported sedation in infants.

Second-generation antihistamines are your best bet for allergies. Cetirizine (Zyrtec), loratadine (Claritin), and fexofenadine (Allegra) all fall under L1-the safest category for breastfeeding. They barely make it into breast milk: loratadine transfers at just 0.04-0.05% of the maternal dose. Studies show no increase in drowsiness, irritability, or feeding issues in babies. One mother on BabyCenter shared: “I’ve taken Zyrtec daily since my son was 3 months old. He sleeps, eats, and plays like normal. No changes at all.”

For coughs, dextromethorphan is the preferred cough suppressant. It transfers in extremely low amounts-only about 0.1% of the mother’s dose. It’s not sedating for babies and doesn’t affect breathing. The InfantRisk Center rates it as L1, meaning it’s considered safe with no known risks.

If you need pain relief, ibuprofen is the top choice. It transfers at only 0.6% of the maternal dose, and levels in milk are far below what would ever affect a baby. It’s also been shown to support milk production, unlike some other painkillers.

For nasal congestion, skip oral decongestants like pseudoephedrine. They can reduce milk supply by up to 24% within 24 hours, according to a 2003 study. Instead, use nasal steroid sprays like fluticasone (Flonase) or budesonide (Rhinocort). These work right where you need them-with less than 0.1% of the dose entering your bloodstream. That means almost nothing reaches your milk.

What to Avoid at All Costs

There are three medications you should never take while breastfeeding unless absolutely no other option exists-and even then, only under strict medical supervision:

• Codeine - High risk of fatal respiratory depression in infants. Banned for use in breastfeeding mothers by the Academy of Breastfeeding Medicine since 2021.
• Diphenhydramine (Benadryl) - Causes noticeable drowsiness in infants, even after a single dose. Avoid unless absolutely necessary.
• Chlorpheniramine and Hydroxyzine - Older antihistamines with similar sedation risks. Not recommended for nursing mothers.

The Breastfeeding Network explicitly states: “Codeine should not be taken while breastfeeding.” The American Academy of Pediatrics says first-generation antihistamines “should be avoided when possible.” And Dr. Thomas Hale, author of Medications and Mothers’ Milk, says: “The risk of respiratory depression in infants outweighs any potential benefit for most breastfeeding mothers.”

Timing and Dosing Tips for Safer Use

Even if you’re taking a medication that’s considered safe, timing matters. If you must use something with a slight risk-like an occasional antihistamine-you can reduce exposure by planning when you take it.

The InfantRisk Center recommends:

• Take the medication right after breastfeeding, not before.
• Wait 3-4 hours before the next feeding. This allows most of the drug to clear from your system.
• Use the lowest effective dose for the shortest time possible.

For example, if you take diphenhydramine (which has a 4-6 hour half-life), waiting 3-4 hours before nursing can reduce infant exposure by more than half. If you’re using a nasal spray, rinse your mouth after use to prevent accidental swallowing.

And here’s something many moms don’t realize: pumping and dumping is rarely necessary. The American Academy of Family Physicians says discarding milk after taking most medications doesn’t help-it just hurts your supply. The exception is codeine, where extreme caution is needed. But for everything else, the drug clears naturally. Focus on timing, not pumping.

Non-Medication Alternatives That Work

You don’t always need pills. Sometimes, simple, drug-free strategies are the safest and most effective.

• Saline nasal sprays - Clear congestion without any risk. Safe for newborns too.
• Humidifiers - Moist air loosens mucus and soothes irritated airways.
• Honey (for moms only) - A teaspoon in warm water can calm a cough. (Never give honey to babies under 1 year.)
• Steam inhalation - Breathe in steam from a bowl of hot water (keep baby away from steam to avoid burns).
• Rest and hydration - Your body heals faster when you’re well-hydrated and rested.

These aren’t just “natural” fixes-they’re evidence-backed, zero-risk options that work.

What to Watch For in Your Baby

Even with the safest medications, keep an eye out for changes in your baby’s behavior. The signs of medication-related sedation are subtle but important:

• Excessive sleepiness-harder to wake for feeds
• Decreased feeding frequency or duration
• Shallow or irregular breathing
• Lethargy or lack of normal responsiveness
• Difficulty latching or sucking

If you notice any of these, stop the medication and contact your pediatrician or lactation consultant immediately. Don’t wait. In newborns, sedation can quickly become dangerous.

How to Make Smart Choices Going Forward

The landscape of breastfeeding-safe medications has changed a lot in the last decade. What was once considered safe-like codeine or Benadryl-is now known to be risky. But there’s also more information available than ever before.

• Always check the LactMed database (run by the NIH) for the latest safety info.
• Look for “non-drowsy” labels on OTC products-those are usually second-generation antihistamines.
• Ask your pharmacist: “Is this safe for breastfeeding?” Don’t assume.
• Use apps like LactaMap, which gives real-time safety ratings based on your baby’s age and your medication.

The key is to be informed, not afraid. You can manage your symptoms without putting your baby at risk. Millions of moms do it every day.