To      :Mary Kay
Re      : Levofloxacin(Levaquin)

Levofloxacin is a the S(-) enantiomer of ofloxacin so its breastmilk
kinetics would probably be similar to ofloxacin (0.05-2.41 mg/Liter..see '97
edition of my book).

In general the quinolones are not preferred antibiotics in breastfeeding
mothers for a number of reasons including pseudomembranous colitis in one
reported infant.   I have two suggestions,  norfloxacin(another quinolone)
apparently does not enter milk in significant levels and could be used
instead.

Secondly,  the fluoroquinolones chelate strongly with magnesium, and
calcium, significantly reducing their oral bioavailability.  I doubt that
signficant levels would be absorbed while dissolved in milk.

Lastly, using quinolone antibiotics in respiratory tract infections is
really rare and I'm wondering why choose this drug?  Is this supported by
culture, or can some other antibiotic be used instead ( like a
cephalosporin).

Regards
Tom Hale, Ph.D.