DOXYCYCLINE

Fetal Risk Summary

See Tetracycline.

Breast Feeding Summary

Doxycycline is excreted into breast milk. Oral doxycycline, 200 mg followed after 24 hours by 100 mg, was given to 15 nursing mothers (1). Milk:plasma ratios determined at 3 and 24 hours after the second dose were 0.3 and 0.4, respectively. Mean milk concentrations were 0.77 and 0.38 µg/mL.

Theoretically, dental staining and inhibition of bone growth could occur in breast-fed infants whose mothers were consuming doxycycline. However, this theoretical possibility seems remote, because in infants exposed to a closely related antibiotic, tetracycline, serum levels were undetectable (less than 0.05 µg/mL) (2). The American Academy of Pediatrics considers tetracycline compatible with breast feeding (3). Three potential problems may exist for the nursing infant even though there are no reports in this regard: modification of bowel flora, direct effects on the infant, and interference with the interpretation of culture results if a fever workup is required.

References

1. Morganti G, Ceccarelli G, Ciaffi EG. Comparative concentrations of a tetracycline antibiotic in serum and maternal milk. Antibiotica 1968;6:216–23.
2. Posner AC, Prigot A, Konicoff NG. Further observations on the use of tetracycline hydrochloride in prophylaxis and treatment of obstetric infections. Antibiotics Annual 1954–55. New York, NY:Medical Encyclopedia, 1955:594–8.
3. Committee on Drugs, American Academy of Pediatrics. The transfer of drugs and other chemicals into human milk. Pediatrics 1994;93:137–50.