Message Number: SG7520 | New FHL Archives Search
Date: 2004-01-20 01:29:49 UTC
Subject: Re: Frontline info
Message-ID: <>

Hi Ruth,
I will try to clear up some of the confusion about
Frontline, ear mites, and rabbits.
Frontline when applied to the skin (or inside the ear)
is not absorbed into the bloodstream, and it does
not cross the blood/brain barrier in ferrets. Thus it does
not cause any problem with the ferret's GABA receptors,
because it stays on the oil layer on the skin (or ears).
Only rarely does Frontline cause any skin irritation on
dogs or cats, and I have not seen this problem in ferrets.
There was a study with Frontline for ferrets (Lewington, J:
Frontline for ferret fleas. University Sydney Postgraduate
Foundation, Veterinary Science Control Therapy Series
189:856, 1996). Both safe and effective.
Similarly Revolution (selamectin), Ivomec or Acarexx
(ivermectin), Milbemite or Interceptor (milbemycin oxime)
can all be used to treat ear mites in ferrets.

Now rabbits are different. Rabbits produce a large, layered
exudate ("ear canker") in response to ear mites. This is probably
due to the fact that rabbits have heterophils instead of neutrophils.
If you clean the ears out, then they will bleed. If you then apply
Frontline to the ears, then it may go into the bloodstream and
cause problems. Also rabbits have very thin skin. The alcohol
content of Frontline spray may cause them problems, and some
Frontline may be absorbed thru the skin and into the bloodstream.
This could cause problems, but I have not seen any side effects with
Frontline in rabbits either. I used to use the low dose (1 spray
per pound) for ear mites and fleas. I would treat the bunny then
recheck the ears after 4 weeks. By then most of the ear exudate
is no longer there. Cleaning the ears at this stage did not cause
any bleeding.
There was a paper using Frontline spray on 50 rabbits at 3 sprays
(3mls) per kg for ear mites with no side effects, but there have been
some reports of side effects in rabbits. Currently I use Revolution
for bunny ear mites and Advantage for bunny flea problems, just to be
on the extra safe side. Perhaps some rabbits are different and Frontline
can cross those rabbit's blood/brain barrier. However just remember it
does not cause side effects in most rabbits.
The big picture is Frontline is safe for ferrets, and the spray version
is the most cost effective way of treating multiple ferrets with fleas or
ear mites.
Hope that helps,
Jerry Murray, DVM