Can I take clarithromycin while pregnant or breastfeeding?

A plain-words look at what the NHS, the US drug label and LactMed say about clarithromycin.

In short

Pregnancy: You can take clarithromycin while pregnant, but other antibiotics may suit you better. Ask your doctor or pharmacist for advice.

Breastfeeding: Clarithromycin can be taken while breastfeeding, as long as your baby is healthy. Speak to your doctor or pharmacist first.

Your doctor, midwife or pharmacist can help you decide.

What this means for you

Pregnancy

Breastfeeding

When to get help

Talk to your doctor or pharmacist

This page is educational, not advice for your own situation. Talk to your doctor, midwife or pharmacist before you start, stop or change any medicine in pregnancy or while breastfeeding.

The details: what each source says

Clarithromycin in pregnancy

The NHS says

You can take clarithromycin while pregnant, but other antibiotics may suit you better. Ask your doctor or pharmacist for advice.

In our words, from the NHS page Clarithromycin (nhs.uk). Contains public sector information licensed under the Open Government Licence v3.0 (OGL v3.0). The NHS does not endorse this site.

The US drug label says

8.1 Pregnancy Risk Summary Based on findings from animal studies, clarithromycin is not recommended for use in pregnant women except in clinical circumstances where no alternative therapy is appropriate. If pregnancy occurs while taking clarithromycin, the patient should be apprised of the potential hazard to the fetus [see Warnings and Precautions (5.7) ]. Limited data from a small number of published human studies with clarithromycin use during pregnancy are insufficient to inform drug-associated risks of major birth defects, miscarriage, or adverse maternal or fetal outcomes. In animal reproduction studies, administration of oral clarithromycin to pregnant mice, rats, rabbits, and monkeys during the period of organogenesis produced malformations in rats (cardiovascular anomalies) and mice (cleft palate) at clinically relevant doses based on body surface area comparison. Fetal effects in mice, rats, and monkeys (e.g., reduced fetal survival, body weight, body weight gain) and implantation losses in rabbits were generally considered to be secondary to maternal toxicity (see Data).

Prescribing label, section “8.1 Pregnancy” (opening excerpt): Clarithromycin (oral), REMEDYREPACK INC. Read the full section on DailyMed. Quoted verbatim; US labels are written for US prescribers and patients.

More on clarithromycin in pregnancy: Bumps (Best Use of Medicines in Pregnancy) leaflet (external site).

Clarithromycin while breastfeeding

The NHS says

Clarithromycin can be taken while breastfeeding, as long as your baby is healthy. Speak to your doctor or pharmacist first.

Very small amounts of clarithromycin get into breast milk, and it's unlikely to cause side effects in your baby.

If you're breastfeeding and have an infection, it's important to treat it, because without treatment it could get worse.

Side effects in breastfed babies from medicines their mother takes are very rare. Even so, it's important to keep an eye on your baby while you take any medicine and breastfeed.

Contact a healthcare professional or call 111 (in the UK) as soon as you can if your baby: is not feeding as well as they usually do or not gaining weight as expected; has an upset stomach, such as diarrhoea or vomiting; has a rash; has oral thrush (a fungal infection in the mouth); has changes in their usual sleep pattern or seems irritable; or seems sweaty.

If your baby has any other symptoms, or you're worried about them, you can still call 111 or get in touch with any healthcare professional.

In our words, from the NHS page Clarithromycin (nhs.uk). Contains public sector information licensed under the Open Government Licence v3.0 (OGL v3.0). The NHS does not endorse this site.

LactMed says

Because of the low levels of clarithromycin in breastmilk and safe administration directly to infants, it is acceptable in nursing mothers. The small amounts in milk are unlikely to cause adverse effects in the infant. Monitor the infant for possible effects on the gastrointestinal flora, such as diarrhea, candidiasis (thrush, diaper rash). Unconfirmed epidemiologic evidence indicates that the risk of infantile hypertrophic pyloric stenosis might be increased by maternal use of macrolide antibiotics during the first two weeks of breastfeeding, but others have questioned this relationship.

“Summary of Use during Lactation”, LactMed record “Clarithromycin” (LM342), quoted verbatim. Everything LactMed reports about Clarithromycin while breastfeeding.

What these words mean

metabolite
a substance made when the body breaks down a medicine

Definitions adapted from the NCI Dictionary of Cancer Terms (National Cancer Institute).

The US prescribing label says

8.2 Lactation Risk Summary Based on limited human data, clarithromycin and its active metabolite 14-OH clarithromycin are present in human milk at less than 2% of the maternal weight-adjusted dose (see Data). In a separate observational study, reported adverse effects on breast-fed children (rash, diarrhea, loss of appetite, somnolence) were comparable to amoxicillin (see Data). No data are available to assess the effects of clarithromycin or 14-OH clarithromycin on milk production. The development and health benefits of breastfeeding should be considered along with the mother’s clinical need for clarithromycin and any potential adverse effects on the breast-fed child from clarithromycin or from the underlying maternal condition. Data Human Serum and milk samples were obtained after 3 days of treatment, at steady state, from one published study of 12 lactating women who were taking clarithromycin 250 mg orally twice daily. Based on the limited data from this study, and assuming milk consumption of 150 mL/kg/day, an exclusively human milk fed infant would receive an estimated average of 136 mcg/kg/day of clarithromycin and its active metabolite, with this maternal dosage regimen.

Prescribing label, section “8.2 Lactation” (opening excerpt): Clarithromycin (oral), REMEDYREPACK INC. Read the full section on DailyMed. Quoted verbatim; US labels are written for US prescribers and patients.

Sources

  1. NHS, Clarithromycin (nhs.uk), page last reviewed 25 March 2026. Paraphrased. Contains public sector information licensed under the Open Government Licence v3.0.
  2. US drug label: Clarithromycin (oral), REMEDYREPACK INC., human prescription drug, label effective 24 June 2026, set ID 9d5848f0-e9f0-4112-a7ca-bcc8ea2e69c6. DailyMed (National Library of Medicine). Public domain; quoted verbatim.
  3. Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development (NICHD), via NCBI Bookshelf, record “Clarithromycin” (LM342), bulk release of 22 September 2026. LactMed on NCBI Bookshelf. Public domain; quoted verbatim. LactMed is a registered trademark of the U.S. Department of Health and Human Services.
  4. Bumps (Best Use of Medicines in Pregnancy), UK Teratology Information Service: Bumps (Best Use of Medicines in Pregnancy) leaflet. Linked, not reproduced.

Sources checked 26 September 2026. How we source and check every page.

Educational summary of named sources, not medical advice.