To all those interested in Flagyl.

        I can't believe all the uproar over this antibiotic.  Years ago,
metronidazole (along with drinking water, salt,  and moms' apple pie) was
suspected of being mutagenic in cell culture assays and rats.  It has never
been documented to be carcinogenic in humans.   Since that time there has
been an incredible miosis concerning its use in lactating women.

        Metronidazle is a good and safe antibiotic typically used in two
major syndromes,  trichomoniasis(protozoa) and anaerobic infections.   It is
well absorbed after oral use and reaches a peak plasma level in 1-2 hrs.
Its plasma half-life in adults is 8.5 hrs,  and in pediatric patients,  25
hrs.   Its milk:plasma ratio is less than 1.8.      It has a wide
distribution and is distributed in most tissues,  including breastmilk.

        For systemic anaerobic infections it is generally given  250 mg TID
for 1-2 weeks.  Milk levels are approximately  6 mg/Liter of milk.   No
untoward effects have ever been reported in lactating infants following this
protocol.

        For treating protozoal infections(trichomoniasis)  many physicians
now recommend the 2 gm STAT dose(8 tablets).  Following this regimen,
approximately 80% of the metronidazole levels in milk are eliminated in 12
hrs,  and virtually completely  gone in 24 hours.   So you can pump and dump
for 12 hrs to 24 hours to avoid exposure to metronidazole.

        For vaginal infections,  the new formulation called Metrogel is
virtually unabsorbed into moms plasma compartment.  The plasma levels
attained following vaginal use is less than 2%  that of one oral 250 mg
tablet.   I see no contraindication to its(Metrogel)  use in lactating women
whatsoever.

       I think we need to be reasonable about this drug.  Prolonged, high
dose exposures may require withdrawal from the breast.  STAT,  high dose
exposures only require brief interruption of breastfeeding(12-24 hrs).
Prolonged,  low dose(250mg TID) protocols  are probably quite safe for
breastfeeding infants,  just observe the infant for unusual symptoms and
withdraw if necessary.

T.W.Hale,Ph.D.
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T.W. Hale, Ph.D.
Associate Professor of Pediatrics
Texas Tech University School of Medicine

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