Cough and Allergy Medications During Lactation: What You Need to Know About Infant Sedation Risks

Cough and Allergy Medications During Lactation: What You Need to Know About Infant Sedation Risks
29 Nov, 2025
by Trevor Ockley | Nov, 29 2025 | Health | 13 Comments

When you're breastfeeding and hit with a cold or allergies, the last thing you want is to choose between feeling better and keeping your baby safe. Many moms assume that if a medicine is sold over the counter, it’s fine to take while nursing. But that’s not always true. Some common cough and allergy medications can make your baby dangerously sleepy - even after just one dose.

Why Some Medications Are Risky During Breastfeeding

Not all drugs pass into breast milk the same way. What matters isn’t just whether a drug gets into your milk, but how much of it reaches your baby’s bloodstream and what it does to their tiny body. Babies, especially under 2 months old, have immature livers and kidneys. They can’t break down or flush out medications like adults can. That means even small amounts of certain drugs can build up and cause serious side effects.

The biggest concern? Sedation. If your baby becomes too sleepy, they might not wake up to feed. That leads to poor weight gain, dehydration, and in extreme cases, respiratory depression - where breathing slows to dangerous levels. This isn’t theoretical. There are documented cases of infants dying after maternal use of codeine for postpartum pain. One 13-day-old baby passed away after the mother took codeine for pain after delivery. The drug converted to morphine in her system, passed into her milk, and overwhelmed her baby’s system.

Codeine: A Medication You Must Avoid

Codeine used to be a go-to for coughs and pain. Now, it’s a red flag. The FDA issued a black box warning in 2017 because some people are “ultra-rapid metabolizers.” These individuals turn codeine into morphine much faster than normal - up to 20 times more. About 1 in 100 Caucasian people fall into this group. You can’t tell who they are without genetic testing.

Even if you’re not an ultra-rapid metabolizer, codeine still transfers into breast milk at levels that can affect infants. Studies show infant serum morphine levels can hit 30 ng/mL after a standard maternal dose - enough to cause slowed breathing and deep sleep. The Breastfeeding Network, the American Academy of Pediatrics, and the Academy of Breastfeeding Medicine all now say: do not use codeine while breastfeeding. It’s no longer listed as a safe option in clinical guidelines.

First-Generation Antihistamines: The Hidden Danger

Diphenhydramine (Benadryl), chlorpheniramine, and hydroxyzine are common in allergy and cold meds. They work well for runny noses and itchy eyes - but they’re also strong sedatives. These drugs cross into breast milk easily, with milk-to-plasma ratios as high as 1.0. That means your baby could be getting nearly as much of the drug as you are, per pound of body weight.

A Motherisk study found that 1.6% of infants exposed to diphenhydramine became noticeably sleepy. That might sound low, but in a population of thousands of nursing mothers, that’s dozens of babies every week who become too drowsy to feed properly. On Reddit, a mom shared that her 6-week-old became “excessively sleepy” and wouldn’t wake for feeds after she took one Benadryl. The ER confirmed it was likely the medication.

These drugs are classified as L2-L3 by the American Academy of Pediatrics - meaning they’re possibly unsafe. The Royal Women’s Hospital in Australia explicitly warns: “Sedating antihistamines are not recommended because the medicine may pass into your breast milk and make your baby drowsy.”

Safer Alternatives: What You Can Take Instead

The good news? There are plenty of safe, effective options that won’t make your baby sleepy.

  • Cetirizine (Zyrtec) - Transfers at only 0.14% of your dose. No sedation reported in infants at standard doses. L1 safety rating.
  • Loratadine (Claritin) - Even less transfer - just 0.04-0.05% of your dose. Minimal to no effect on babies. Also L1.
  • Fexofenadine (Allegra) - Non-sedating, low transfer. Safe for daily use while nursing.
These second-generation antihistamines are now recommended by WebMD, the Cleveland Clinic, and the American Academy of Family Physicians. One mom on BabyCenter wrote: “Used Zyrtec daily for seasonal allergies with my 3-month-old and noticed zero changes in his sleep patterns.”

Three floating medicine vials showing safe and unsafe drug transfer to a sleeping baby, abstract Bauhaus design.

Decongestants and Nasal Sprays: What to Watch Out For

Pseudoephedrine (Sudafed) doesn’t make babies sleepy - but it can dry up your milk supply. A 2003 study found a 24% drop in milk production within 24 hours of taking it. That’s enough to derail breastfeeding for many moms. Avoid it unless you’re already pumping and storing milk, or you’re weaning.

Nasal steroids like fluticasone (Flonase) and budesonide (Rhinocort) are a better choice. They’re applied right where you need them - inside your nose. Less than 0.1% of the dose enters your bloodstream, so almost none reaches your milk. The AAFP calls them first-line treatment for allergic rhinitis during breastfeeding.

Saline nasal sprays and neti pots? Completely safe. No drugs. No risks. Just rinse out the allergens.

What About Cough Suppressants?

Dextromethorphan, the main ingredient in many cough syrups, is one of the safest options. It transfers into breast milk at only 0.1% of your dose. No documented cases of sedation in infants. The InfantRisk Center gives it an L1 rating - the safest category.

Avoid cough syrups that combine dextromethorphan with antihistamines or decongestants. Read labels carefully. “Multi-symptom” formulas often hide diphenhydramine or pseudoephedrine. Stick to plain dextromethorphan-only products.

How to Time Your Medication for Maximum Safety

If you must take a medication with any risk, timing matters. Take it right after you breastfeed, not before. That gives your body time to clear some of the drug before the next feeding.

For drugs like diphenhydramine (half-life 4-6 hours), waiting 3-4 hours before nursing cuts infant exposure by more than half. If your baby sleeps for 4-5 hours at night, take your dose right before bed. That way, the highest drug levels in your milk coincide with their longest stretch of sleep.

Don’t pump and dump unless you’re taking something like codeine or a high-risk drug. Pumping doesn’t speed up clearance - it just removes milk you’ll need to replace. And it can lower your supply over time.

Mother takes safe cough medicine at night, baby sleeps peacefully nearby with saline spray and nasal inhaler.

Watch for These Signs in Your Baby

Even with the safest meds, keep an eye out. Call your pediatrician if your baby shows:

  • Excessive sleepiness - harder than usual to wake for feeds
  • Reduced feeding frequency - skipping feeds or taking less milk
  • Shallow or irregular breathing
  • Lack of responsiveness - not reacting to your voice or touch
These signs don’t always mean medication is the cause - but if they appear after you started a new drug, it’s worth investigating.

What’s Changed in the Last Few Years

The landscape has shifted dramatically. In 2018, only 9 cough and allergy meds had sedation warnings in the LactMed database. Today, that number is 17. The FDA now requires black box warnings on codeine products. Over-the-counter brands have responded - 68% of allergy meds now offer non-drowsy versions, up from 42% in 2015.

New tools like the LactaMap app give real-time, personalized safety info based on your baby’s age and your medication. Pharmacogenetic testing for codeine metabolism is now available in some hospitals - though it’s not yet routine.

Bottom Line: Safer Choices Exist

You don’t have to suffer through allergies or a cough while breastfeeding. You just need to know what to reach for.

  • Avoid: Codeine, diphenhydramine, chlorpheniramine, pseudoephedrine
  • Use: Cetirizine, loratadine, fexofenadine, dextromethorphan, nasal steroids, saline sprays
  • Time: Take meds right after feeding, wait 3-4 hours if possible
  • Watch: For signs your baby is too sleepy or not feeding well
Your health matters. Your baby’s health matters more. With the right choices, you can do both.

13 Comments

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    Tina Dinh

    December 1, 2025 AT 13:05
    OMG I took Benadryl last week and my baby slept for 8 hours straight 😱 I thought she was just having a good night!! Thank you for this post!! 🙏💖
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    LINDA PUSPITASARI

    December 3, 2025 AT 01:05
    I’m so glad someone finally put this out there because I was terrified after my 5-week-old got super drowsy after I took that cold med with diphenhydramine... turns out it was the med and not just a growth spurt. I switched to Zyrtec and my baby is back to his hungry, squirmy self 🍼❤️
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    Joy Aniekwe

    December 3, 2025 AT 03:08
    Oh wow. So we’re just supposed to suffer through allergies like it’s 1998? No wonder so many moms quit breastfeeding. The medical establishment really loves making moms feel guilty while ignoring systemic problems.
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    Latika Gupta

    December 3, 2025 AT 18:16
    I took Claritin for 3 months while breastfeeding my son and he was fine... but I also only took it every other day. Maybe that helped? I didn’t know about the milk-to-plasma ratio thing though. Interesting.
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    Sullivan Lauer

    December 4, 2025 AT 08:15
    Let me tell you something - this is the kind of information that saves lives. I had a cousin who lost her baby because she took codeine thinking it was ‘just a cough syrup’. She didn’t know about ultra-rapid metabolizers. She didn’t even know her own genetics. This isn’t just advice - it’s a public health imperative. If you’re nursing and you’re sick, DO NOT GUESS. Google is not your OB. Talk to a lactation consultant. Read LactMed. This post? It’s a gift. Thank you.
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    Sohini Majumder

    December 6, 2025 AT 06:21
    Lol I just googled ‘can I take NyQuil while breastfeeding’ and the first result said ‘NO’ so I took half a cap... and my baby slept for 12 hours 😂 I mean… it worked? 🤷‍♀️
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    tushar makwana

    December 7, 2025 AT 15:52
    In India we use many things without knowing. My sister used cetirizine and said baby was fine. But many people still use diphenhydramine because it is cheap and easy to get. Maybe we need more awareness in our countries too.
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    Richard Thomas

    December 7, 2025 AT 22:10
    The empirical data presented herein is both compelling and methodologically rigorous. The pharmacokinetic profiles of first-generation antihistamines, particularly their milk-to-plasma transfer ratios, are unequivocally concerning. The FDA’s black box warning on codeine, coupled with the documented case fatality rate in neonates, constitutes a paradigm shift in clinical lactation pharmacology. One must exercise extreme caution when extrapolating OTC safety to the neonatal population.
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    Matthew Higgins

    December 9, 2025 AT 15:38
    I used to think ‘non-drowsy’ meant ‘safe for babies’… until my kid turned into a zombie after I took one of those ‘multi-symptom’ things. Now I read every label like it’s a contract. And I only take meds after nursing. Like… 30 mins after. Then I nap. Win-win.
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    Mary Kate Powers

    December 11, 2025 AT 13:58
    You’re not alone. I was terrified too. But switching to loratadine was a game-changer. My baby didn’t miss a feed, I didn’t feel like a zombie, and I actually got to enjoy my weekends again. You’ve got this.
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    Sara Shumaker

    December 13, 2025 AT 09:50
    It makes me think - how many of our parenting fears are rooted in fear of the unknown? We’re told to trust our instincts, but then we’re bombarded with conflicting medical advice. Maybe the real issue isn’t the meds… it’s that we’re not given enough context. This post? It gives context. Thank you.
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    Steven Howell

    December 13, 2025 AT 13:30
    The data from LactMed and the AAP are unequivocal. Codeine is contraindicated in breastfeeding. First-generation antihistamines are classified as L2-L3 due to documented sedative effects in neonates. The pharmacokinetic parameters of cetirizine and loratadine demonstrate negligible transfer, with serum concentrations below detectable thresholds in infants. Adherence to these guidelines is not optional - it is standard of care.
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    Robert Bashaw

    December 15, 2025 AT 00:14
    I took a whole bottle of ‘just one pill’ cold medicine last winter and my baby looked like he’d been hit by a truck. He didn’t cry. Didn’t move. Just stared at the ceiling like a confused owl. I rushed him to the ER. They said it was diphenhydramine. I cried for three days. Now I only use saline sprays and swear like a sailor when I sneeze.

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