Drug Levels and Effects:

Summary of Use during Lactation:

A number of reviews have stated thattetracyclinesare contraindicated during breastfeeding because of possible staining of infants' dental enamel or bone deposition oftetracyclines. However, a close examination of available literature indicates that there is not likely to be harm in short-term use of oxytetracycline during lactation because milk levels are low and absorption by the infant is inhibited by the calcium in breastmilk. Short-term use of oxytetracycline is acceptable in nursing mothers. As a theoretical precaution, avoid prolonged or repeat courses during nursing. Monitor the infant for rash and for possible effects on the gastrointestinal flora, such as diarrhea or candidiasis (thrush, diaper rash).

Drug Levels:

Maternal Levels.

In an old study using a microbiologic assay, 5 women in the first week postpartum were given oxytetracycline in dosages ranging from 2 to 4 grams daily in single or divided doses. Oxytetracycline generally did not appear in milk for the first 24 hours. Concentrations then ranged from 0.25 to 1 mg/L until about a day following discontinuation of the drug.[1]

In another old study using a microbiologic assay, milk oxytetracycline levels were in an unspecified number of nursing mothers at 9 am after various dosages of oxytetracycline during the previous days. Whether they had mastitis and the time postpartum were not stated. Milk levels increased to as high as 3 mg/L after a daily dose of 1.5 grams orally for 3 days. Milk levels increased to 3 mg/L after a daily dose of 2 grams orally for 3 days.[2]

Two women were given 1.5 grams daily of oral oxytetracycline. Milk levels ranged from 0.7 to 1.1 mg/L with the peak occurring 7 hours after the dose. The authors estimated that a breastfed infant would receive 300 mcg daily of oxytetracycline in milk.[3]

Infant Levels.

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

Effects in Breastfed Infants:

No adverse effects were noted in an unspecified number of breastfed infants whose mothers were taking oral oxytetracycline 1.5 or 2 g daily for 3 days. Ages of the infants and extent of breastfeeding were not stated.[2]

Possible Effects on Lactation:

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

Alternate Drugs to Consider:



1. Ottolenghi-Preti GF, Massironi A. [Terramycin in lactation; specific method of determination]. Ann Ostet Ginecol. 1952;74:746-58. PMID:13031337
2. Gruner JM. [The excretion of terramycin andtetracyclinein human milk]. Geburtshilfe Frauenheilkd. 1955;15:354-60. PMID:14380696
3. Borderon E, Soutoul JH et al. [Excretion of antibiotics in human milk]. Med Mal Infect. 1975;5:373-6.

Substance Identification:

Substance Name:


CAS Registry Number:


Drug Class:

  • Antiinfective Agents

  • Antibacterial Agents

  • Tetracyclines

    Administrative Information:

    LactMed Record Number:


    Last Revision Date:

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