>... I ran to see what I've been putting in my Claudette's eyes for an
>infection, prescribed by her ferret-experienced vet.  Gentocin drops
>(gentamicin sulfate, ophthalmic solution).  She is on a second round of
>it, with a few weeks in between, as we only put it in the left eye, which
>cleared up, but then the right eye became goopy, so we're putting it in
>both for a week.  She has lost weight, two to three ounces recently in
>the past month or two.  I haven't liked the look of her eyes, a little
>bulgy.  Today she had terrible diarrhea, though she has loose seedy stool
>generally and we haven't been able to find out why.  Is THIS what you're
>not supposed to give to ferrets, or are you talking about an oral
>antibiotic?  Oh... Okay.  I searched back a few FML's and see it's an
>injectable, and was discussed by Dr. Williams (hi Dr. Williams!) at
>Ferrets 2000.  However, eye drops can leak out a bit and could get
>licked, though it should be minimal ingestion.
 
FML'ers -
 
Please let me clarify my statements on Gentamicin - (Gentocin is the common
trade name) -
 
Gentamicin, an aminoglycoside antibiotic commonly used in dogs and cats
to treat certain types of infections is a poor choice of antibiotic for
SYSTEMIC administration in the ferret.  This means using it orally or more
commonly, as an injectable.  It is especially bad when used in the absence
of definite indication for its use, such as a bacterial culture, which
evidence that the bacteria is only susceptible to this drug.  In such
cases, careful dosing and close monitoring of renal function is imperative.
 
Ferrets appear to be uniquely sensitive to this antibiotic, even though
there are dosages published for it in the ferret.  In a recent article I
wrote on Therapeutics of Ferrets in the Veterinary Clinics of North
America, while I included a dosage for this antibiotic, I also gave major
cautions in its empiric use in the ferret.
 
TOPICAL administration of gentamicin is likely safe, such as eye drops
or ear drops applied in areas where the epidermis is not broken.  Broken
epidermis may lead to systemic absorption, or licking stray drops from the
eyes of ears, but it is highly unlikely that sufficient systemic levels
could be achieved to do any damage.
 
Gentamicin may result in ototoxicity (resulting in deafness) and in
slightly higher doses, results in acute kidney toxicity.  If the dosage
is sufficient, the damage to the kidneys may be life-threatening.  While
deafness is not life-threatening, I think we tend to underestimate the
possibility of its occurrence, especially as it is poorly measured in
ferrets.
 
Bottom line - if there is no distinct indication for gentamicin use in
ferrets, it is always better to use another antibiotic.  But don't run
and throw out your eye drops and ear drops - just ask for another type on
refill.
 
Bruce Williams, DVM
[Posted in FML issue 3185]