Couple of quick references:
From DML website - Tiberal affects taste of BM, "breastfeeding should be discontinued until ~48 hours after completion of treatment since they give the milk a bitter taste"
BUT, from Dr Thomas Hale (BF pharmacologist):
Dear Dr Hale,
Baby 1 month old. Mother receiving ornidazole (Tiberal(R))1g q24hIV and amikicin and vancomycin (perforated intestine). The use of amika and vanco is not contraindicated with BF. What about ornidazole?
Thanks,
Regards, Dr Greet Stevens, pediatrician, IBCLC, Belgium
Tom Hale Ph.D. posted on Monday, April 26, 2004 - 03:19 pm
Dr. Stevens:
We unfortunately do not have data yet published on breast milk levels of ornidazole. It is not available here in the USA, but it is similar to metronidazole that we use all the time here. While similar in structure to metronidazole it is actually considered safer, as its side effect profile is better than metronidazole.
Thus from this data I'd suggest its probably quite safe to use in breastfeeding mothers. We use metronidazole all the time in infants and in breastfeeding mothers due to its high degree of safety.
Tom Hale Ph.D. (http://neonatal.ttuhsc.edu/discus/messages/40/1819.html?1083010756)

to your GP.