>Flagyl in a topical cream.  You just rub a measured amount onto the skin
>and then just let it work.
 
Dear X:
 
I have serious concerns about the use of transdermal Flagyl.  I have
discussed this with other vets on this list, as well as pharmacists.
Metronidazole is used in ferrets for treatment of two agents - one a
bacteria (Helicobacter) and one a protozoan (Giardia).  Both of these
agents are extracellular and live in the lumen of the stomach and
intestine, respectively.
 
As these agents live outside the tissues of the body, in the space within
the gut, we rely on oral administration to get the proper dosage of the
antibiotic to these pathogens.  When you administer it with a cream, you
get a low blood level of the antibiotic, which likely does not get into
the lumen of the gut at all, and is probably of no effect.
 
Metronidazole creams are effective in human females for vaginal
infections, in which it is deposited into the vagina where it can be
effective against some pathogens, but is not used in that form for GI
problems.
 
With kindest regards,
Bruce Williams, DVM
[Posted in FML issue 3623]