RE:  Metronidazole

I just today ran across an interesting article that I have failed to see
before concerning metronidazole use in breastfeeding women. For those of you
fighting this battle,  below is good data suggesting it is safe to use in
breastfeeding moms.

Regards
Tom Hale, Ph.D.
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Passmore CM. McElnay JC. Rainey EA. D'Arcy PF. Metronidazole excretion in
human milk and its effect on the suckling neonate.  British Journal of
Clinical Pharmacology. 26(1):45-51, 1988 Jul.

Abstract
1. Milk and plasma metronidazole and hydroxymetronidazole concentrations
were measured in 12 breast-feeding patients following multiple doses of
metronidazole (400 mg three times daily). All patients received
metronidazole in combination with other broad spectrum antibiotics.
2. Plasma concentrations of both parent drug and metabolite were measured in
seven suckling infants. Thirty-five infants were monitored for adverse
reactions to maternal metronidazole therapy and two further groups of
suckling infants, those whose mothers received either ampicillin alone or no
drug therapy, were recruited as controls.
3. The mean milk to plasma ratio (M/P) was 0.9 for metronidazole and 0.76
for hydroxymetronidazole while the mean milk metronidazole concentrations
(around Cmax) were 15.5 micrograms ml-1. The mean milk hydroxymetronidazole
concentration was 5.7 micrograms ml-1.
4. Infant plasma metronidazole concentrations ranged from 1.27 micrograms
ml-1 to 2.41 micrograms ml-1, and the corresponding   hydroxymetronidazole
concentrations from 1.1 to 2.4 micrograms ml-1.
5. There were no significant increases in adverse effects in infants which
could be attributable to maternal metronidazole therapy.
6. Metronidazole was excreted in milk at concentrations which caused no
serious reactions in the infants studied. The drug may therefore be
administered at doses of 400 mg three times daily to mothers wishing to
breast-feed their infants.