Drug Levels and Effects:

Summary of Use during Lactation:

Levofloxacin is the


-enantiomer of the fluoroquinolone, ofloxacin. Fluoroquinolones such as levofloxacin have traditionally not been used in infants because of concern about adverse effects on the infants' developing joints. However, recent studies indicate little risk.[1][2] The calcium in milk might prevent absorption of the small amounts of fluoroquinolones in milk,[3] but insufficient data exist to prove or disprove this assertion. Short-term use of levofloxacin is acceptable in nursing mothers. Avoiding breastfeeding between 4 to 6 hours after a dose should decrease the exposure of the infant to levofloxacin in breastmilk. Maternal use of an eye drop that contains levofloxacin presents negligible risk for the nursing infant.

Drug Levels:

Levofloxacin is the levo isomer of the racemic drugmixture, ofloxacin.

Maternal Levels

Ten lactating women (time postpartum not stated) were given the racemicmixture, ofloxacin, 400 mg orally every 12 hours for 3 doses. Milk ofloxacin was measured after the third dose. The highest levels averaging 2.4 mg/L occurred 2 hours after the dose. Average milk levels then fell as follows: 1.9 mg/L at 4 hours; 1.25 mg/L at 6 hours; 0.64 mg/L at 9 hours; 0.29 mg/L at 12 hours; and 0.05 mg/L at 24 hours after the dose.[4] Using the peak milk level data from this study, an exclusively breastfed infant would receive an estimated maximum of 0.36 mg/kg daily with this maternal dosage regimen.

One woman was given levofloxacin 500 mg daily intravenously for 9 days, then orally for 17 days. Twenty-six breastmilk samples were obtained beginning on day 10 of therapy and continued for 6 days after the discontinuation of therapy. A pharmacokinetic model that was developed predicted that a peak milk level of 8.2 mg/L would occur 5 hours after the dose. The milk levels fell with an estimated half-life of 7 hours. Traces of levofloxacin were still detectable in breastmilk 65 hours after the dose. The authors calculated that an exclusively breastfed infant whose mother was taking 500 mg daily would receive 1.25 mg daily in breastmilk which is far below the dose of levofloxacin used in children.[5]

Infant Levels

Relevant published information was not found as of the revision date.

Effects in Breastfed Infants:

Relevant published information was not found as of the revision date.

Possible Effects on Lactation:

Relevant published information was not found as of the revision date.

Alternate Drugs to Consider:



1. Gurpinar AN B, Balkan E, Kilic N et al. The effects of a fluoroquinolone on the growth and development of infants. J Int Med Res. 1997;25:302-6. PMID:9364293
2. van den Oever HL, Versteegh FG, Thewessen EA et al. Ciprofloxacin in preterm neonates: case report and review of the literature. Eur J Pediatr. 1998;157:843-5. PMID:9809826
3. Fleiss PM. The effect of maternal medications on breast-feeding infants. J Hum Lact. 1992;8:7. Letter. PMID:1558663
4. Giamarellou H, Kolokythas E, Petrikkos G et al. Pharmacokinetics of three newer quinolones in pregnant and lactating women. Am J Med. 1989;87(suppl 5A):49S-51S. PMID:2589384
5. Cahill JB Jr, Bailey EM, Chien S et al. Levofloxacin secretion in breast milk: a case report. Pharmacotherapy. 2005;25:116-8. PMID:15767227

Substance Identification:

Substance Name:


CAS Registry Number:


Drug Class:

  • Antiinfective Agents

  • Antibacterial Agents

  • Quinolones

  • Fluoroquinolones

  • Administrative Information:

    LactMed Record Number:


    Last Revision Date:

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