Many new mothers worry: Can I take this medication while breastfeeding? The fear isn’t irrational - you’re not just treating yourself, you’re protecting your baby too. But here’s the truth: most medications are safe. In fact, less than 5% of drugs are truly contraindicated during breastfeeding. The real problem isn’t the medicine - it’s the misinformation. Too many moms stop nursing because a doctor says, “Better safe than sorry,” when the evidence says otherwise.
What Makes a Medication Safe During Breastfeeding?
Not all drugs behave the same way in breast milk. Safety isn’t about whether a drug gets into milk - it’s about how much, how long it stays, and what it does to your baby. The key metric doctors use is the
Relative Infant Dose (RID). This measures how much of the drug your baby actually absorbs through breast milk compared to your dose. If the RID is under 10%, it’s generally considered low risk. Most common medications have RIDs under 2%.
For example, if you take 500 mg of ibuprofen, your baby might get about 1 mg through breast milk. That’s less than what you’d give a newborn for fever. And because many drugs don’t absorb well in a baby’s gut, even less makes it into their bloodstream.
The best resources for this data? LactMed, run by the U.S. National Library of Medicine, and the InfantRisk Center. These aren’t guesswork sites - they pull from peer-reviewed studies, pharmacokinetic models, and real-world infant monitoring. They tell you exactly how much drug ends up in milk, whether it’s been linked to side effects, and how long it lingers.
Pain Relief: Acetaminophen and Ibuprofen Are Your Go-To
If you’re dealing with headaches, sore muscles, or postpartum pain, acetaminophen (Tylenol) and ibuprofen (Advil, Motrin) are the gold standard. Both have RIDs below 1%, meaning your baby absorbs almost nothing. They’re also safe for direct infant use - you’re giving your baby the same drug, just in a smaller dose.
Ibuprofen breaks down quickly in your body and doesn’t build up in milk. Acetaminophen is even cleaner - it’s excreted mostly through urine, with almost no trace in breast milk. Both are recommended by the American Academy of Family Physicians, Mayo Clinic, and the CDC. No need to time feedings. No need to pump and dump.
Skip naproxen (Aleve) for anything beyond a single dose. Its half-life is over 12 hours, and it’s been linked to rare cases of infant bleeding and anemia. Opioids? Avoid codeine completely. Some people metabolize it into morphine too quickly, and that can overdose a baby. Morphine and hydromorphone are safer if used short-term and at the lowest dose possible - but always monitor your baby for excessive sleepiness or trouble feeding.
Antibiotics: Most Are Fine - But Watch for Diarrhea
If you’ve got an infection, you’re not doing your baby any favors by skipping antibiotics. The good news? Penicillins like amoxicillin, cephalosporins like cephalexin, and vancomycin are all safe. Their RIDs are low, and there’s no evidence of long-term harm.
Macrolides like azithromycin are preferred over erythromycin. Erythromycin has a tiny risk of causing pyloric stenosis - a rare but serious condition that causes vomiting in infants. Azithromycin transfers minimally and has no such reports.
Fluoroquinolones like ciprofloxacin? Technically safe. Animal studies raised concerns about joint damage, but no human babies have shown issues. Still, they’re not first-line unless you really need them. Tetracyclines like doxycycline? Safe for short courses (under 21 days). Long-term use could theoretically affect tooth color, but no cases have been documented in breastfed infants.
Clindamycin? Use with caution. It can upset your baby’s gut and cause diarrhea. If you’re on it, watch for loose stools or fussiness.
Antidepressants and Anxiety Meds: Sertraline Leads the Pack
Postpartum depression affects 1 in 7 new mothers. Stopping breastfeeding to take medication shouldn’t be the trade-off. SSRIs are the most studied class, and sertraline (Zoloft) is the clear winner. Its RID is around 1.7-7%, but infant blood levels are often undetectable. It’s been used safely for decades, with no long-term developmental issues in follow-up studies.
Paroxetine (Paxil) is also safe, though slightly higher transfer. Fluoxetine (Prozac)? Avoid it if you can. Its half-life is 4-6 days. It builds up in your system - and in your baby’s. Studies show about 2% of exposed infants develop irritability or poor feeding.
For anxiety, lorazepam (Ativan) is the best benzodiazepine. Short half-life, low transfer. Clonazepam? Too long-lasting. It can make your baby sleepy or sluggish. Always use the lowest dose for the shortest time.
Antipsychotics like quetiapine (Seroquel) and risperidone (Risperdal) are also safe at standard doses. Long-term studies show normal growth and development in babies exposed through breast milk.
Allergy Meds: Skip the Old-School Antihistamines
Seasonal allergies? You don’t need to suffer. First-generation antihistamines like diphenhydramine (Benadryl) are a bad idea. They cross into milk easily, and babies can get drowsy, fussy, or even have trouble feeding. One study found 5% of infants exposed to Benadryl showed signs of sedation.
Stick to second-generation options: loratadine (Claritin), cetirizine (Zyrtec), and fexofenadine (Allegra). All have RIDs under 0.5%. No sedation. No feeding issues. No documented side effects in over 150 case reports.
Nasal sprays like fluticasone (Flonase) and budesonide (Rhinocort) are even better. They’re designed to act locally in your nose. Less than 1% enters your bloodstream - so almost nothing reaches your milk. Perfect for runny noses and congestion.
Avoid pseudoephedrine (Sudafed). It reduces milk supply by up to 24% in many women. That’s not a small drop - it’s enough to make breastfeeding unsustainable. Use saline sprays or steam inhalation instead.
What to Avoid Completely
There are a few drugs that truly aren’t safe. Radioactive iodine (I-131) for thyroid treatment? You must stop breastfeeding for 3-6 weeks. The radiation can damage your baby’s thyroid. No exceptions.
Chemotherapy drugs? Almost all require you to pause breastfeeding. The risk of long-term damage to a developing infant is too high. Talk to your oncologist - some newer targeted therapies may allow limited breastfeeding, but only under strict monitoring.
Lithium? It’s tricky. It passes into milk at 30-50% of your blood level. Infants can build up toxic levels quickly. If you’re on lithium, your baby needs weekly blood tests to check levels. If you can’t do that, formula may be the safer choice.
Herbal supplements? Don’t assume they’re safe. Many haven’t been studied in breastfeeding women. St. John’s Wort, for example, can cause colic or irritability. Kava and valerian can cause drowsiness. Always check with a provider before taking anything labeled “natural.”
What to Do If You’re Unsure
If you’re prescribed something new, don’t guess. Don’t rely on Google or a friend’s opinion. Use LactMed - it’s free, updated quarterly, and backed by the NIH. Type in the drug name, and you’ll get: RID, milk-to-plasma ratio, infant blood levels, and documented side effects.
Call the InfantRisk Center (1-806-352-2519). They’re staffed by pharmacists and researchers who specialize in lactation. They answer over 15,000 calls a year. No judgment. No sales pitch. Just facts.
Talk to your pediatrician. Ask: “Is this safe for a baby this age?” Not “Can I take this while breastfeeding?” The answer will be clearer if you frame it around your baby’s health.
Myth: If It’s Safe for Babies, It’s Safe for Breastfeeding
This is a useful rule of thumb - and it’s mostly true. If a drug is approved for infants, it’s likely safe in breast milk. But there are exceptions. Some drugs are safe for babies to swallow - but not safe if they’re absorbed through milk over weeks. Lithium is one. Others, like certain antivirals or immunosuppressants, may be okay for older infants but risky for newborns.
Always verify. The rule helps you eliminate the obvious dangers - but it doesn’t replace evidence.
Final Thought: Breastfeeding Is Worth Protecting
About 10-15% of mothers stop breastfeeding because they think a medication isn’t safe. In most cases, that decision is based on outdated advice or fear, not science. You’re not being selfish by taking a needed medication. You’re being responsible.
Your health matters. Your mental health matters. Your ability to care for your baby matters. There’s almost always a safe option. You just need the right information.
Use LactMed. Talk to a specialist. Ask questions. Don’t let misinformation cost you the benefits of breastfeeding - for you, and for your baby.
Juan Reibelo
24 01 26 / 04:08 AMI used to panic every time I needed an antibiotic-until I found LactMed. Now I check before I take anything. Seriously, it’s free, it’s scientific, and it saved my breastfeeding journey. No more guessing. No more tears. Just facts.
My OB told me to stop nursing for ibuprofen. I cried for an hour. Then I looked it up. Turns out, I was giving my baby less than a drop of the stuff. I felt so stupid-and so relieved.
Phil Maxwell
26 01 26 / 02:38 AMYeah, I’ve been using sertraline since week two postpartum. Baby’s been fine. Sleeps great, feeds well. I used to feel guilty taking it-like I was betraying my body or something. But the data says otherwise. My pediatrician didn’t even blink when I told her I was on it. Just said, ‘Good. You need to be well too.’
Amelia Williams
27 01 26 / 13:58 PMOMG YES. I was on Zoloft for 8 months while nursing my twins. One of them had a tiny bit of fussiness at first, but it cleared up in a week. No one warned me about the myth that ‘if it’s safe for babies, it’s safe for breastfeeding’-but honestly, that’s the biggest trap. My cousin quit breastfeeding because she was told Zyrtec was unsafe. She didn’t even know Claritin existed. So much unnecessary suffering.
Also, pseudoephedrine? I lost 30% of my supply in 48 hours. Never again. Saline spray and steam now. Life-changing.
Dolores Rider
27 01 26 / 16:25 PMTHEY’RE LYING TO US. I swear, Big Pharma and the AAP are in cahoots. Why do you think they push these ‘safe’ meds? So you keep nursing and don’t sue them when your kid turns out autistic? I read a paper that said SSRIs alter serotonin receptors in infant brains-long-term! They just don’t publish the scary parts.
My baby cried for 14 hours straight after I took amoxicillin. Coincidence? I think not. 🤔💊
Vatsal Patel
27 01 26 / 22:45 PMSo let me get this straight-you’re telling me a woman can take lithium, which transfers at 50% of maternal blood levels, and it’s ‘manageable’? But if she takes a little ibuprofen, she’s a hero? That’s not science. That’s selective morality.
And don’t get me started on ‘natural’ supplements. St. John’s Wort is literally a monoamine oxidase inhibitor. You wouldn’t give that to a toddler, but you’ll let your baby sip it through breast milk? Logic is dead.
Also, why does no one mention that LactMed is funded by the NIH? Who funds the NIH? Who funds the drug companies? The circle of trust is a Möbius strip.
Sharon Biggins
28 01 26 / 18:33 PMi just wanted to say thank you for this post. i was so scared to take anything after my c-section. i thought i had to choose between being in pain or losing my bond with my baby. but reading this made me feel like i’m not alone.
also, i spelled ‘ibuprofen’ wrong in my notes for like 3 weeks. i kept writing ‘ibuprofren’. lol. but i looked it up every time. you’re right-information is power.
my baby is 6 months now and thriving. i’m on sertraline. i’m alive. and i’m nursing. and that’s enough.
John McGuirk
28 01 26 / 23:55 PMEveryone says ‘don’t worry’ but nobody talks about the 0.001% of cases where babies get liver damage from antibiotics. That’s not a number-that’s a baby. And now you’re telling me to trust a website run by the government? The same government that said thalidomide was fine?
My cousin’s kid had seizures after she took cipro. They said ‘rare.’ But rare doesn’t mean impossible. And now she can’t walk. So yeah, I’m not taking any chances. Formula for life.
lorraine england
29 01 26 / 15:20 PMSo I took a single dose of naproxen after my delivery because the pain was unbearable. My baby was a little extra sleepy for 12 hours. I panicked. Called my lactation consultant. She said, ‘It’s fine. One dose. You’re okay.’
But you know what? I didn’t take another one. I switched to ibuprofen. And I’m so glad I did. I just wish more doctors would say: ‘Here’s what’s safest-not just what’s available.’
Also, I used Flonase for my allergies and it was a miracle. No drowsiness. No supply drop. Just clear sinuses and happy baby. Thank you for mentioning that.
Himanshu Singh
29 01 26 / 20:40 PMLove this post. Really. But I think we’re missing the bigger picture. Why are we even asking if we can take meds while breastfeeding? Why isn’t the system designed so that mothers don’t have to choose between health and feeding?
It’s not about the drugs. It’s about the lack of support. If we had better postpartum care, mental health access, and paid leave-maybe fewer moms would be in pain or depression to begin with.
Still, thank you for the data. It’s a lifeline. 🙏
Husain Atther
31 01 26 / 06:51 AMThe data presented here is accurate and well-sourced. However, I would like to emphasize the importance of individual variability. While RID values are statistically reliable, infant metabolism, gut permeability, and age play critical roles. A drug that is safe for a 4-month-old may not be ideal for a 3-day-old.
Moreover, the cumulative effect of polypharmacy-multiple medications taken simultaneously-is rarely studied in breastfeeding populations. This is a gap in the literature that deserves attention.
That said, LactMed remains the gold standard. I recommend every new mother bookmark it.
Elizabeth Cannon
1 02 26 / 07:46 AMthank you for this. i’m a nurse and i’ve seen so many moms cry because they were told to stop nursing for ‘safety.’ i’ve even had doctors say ‘just pump and dump’ for ibuprofen. like it’s some kind of sin.
we need to stop treating breastfeeding like it’s fragile. it’s not. moms are strong. and medicine isn’t the enemy.
i’m gonna print this out and hand it to every new mom i see. seriously. this is the info we need to be sharing.
Tommy Sandri
2 02 26 / 04:58 AMIt is worth noting that the Relative Infant Dose (RID) is a theoretical construct based on average pharmacokinetic parameters. While useful, it does not account for genetic polymorphisms in infant drug metabolism, which can vary significantly across populations. For instance, CYP2D6 ultra-rapid metabolizers in certain ethnic groups may process codeine differently, leading to unpredictable morphine exposure.
Additionally, while LactMed is a commendable resource, it does not always reflect real-world pharmacovigilance data from low-resource settings, where infant monitoring is limited. Caution, therefore, remains prudent when extrapolating guidelines across diverse contexts.
Nonetheless, the evidence base supporting most commonly used medications is robust and should be communicated with confidence.
Sushrita Chakraborty
2 02 26 / 18:01 PMThank you for this comprehensive, evidence-based guide. As a pharmacologist from India, I’ve seen too many mothers discontinue breastfeeding due to misinformation propagated by well-meaning but untrained healthcare providers.
The emphasis on LactMed and InfantRisk Center is spot-on. In my country, many doctors still rely on outdated textbooks from the 1990s. I’ve personally trained 12 OB-GYN residents in the last year using these resources.
One small addition: for mothers on antiretrovirals in high-HIV-prevalence areas, WHO guidelines now support breastfeeding with ART, as the risk of HIV transmission is lower than the risk of infant mortality from formula feeding. This nuance is often overlooked.
Knowledge is power. And you’ve just empowered countless mothers.