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There
comes a point where you realize that however excellent your vet is,
the ultimate responsibility for your dog, this huge part of your
life that you love, is in your hands. It tends to make you
what many vets might call a pain in the neck when you're not around,
though others, there are some, will appreciate your willingness to
be a part of your dog's care since no
vet can know everything about everything
and
the information you dig up and bring them from reliable sources may
very well trigger a new line of thought, even lead to a correct
diagnosis and eventual recovery from some pretty bad illnesses.
Deb
Histen has an 18 month old Golden Retriever named Henry who has
epilepsy. It hit Deb pretty hard and since she's learned the
hard way in the past that you have to take an active interest in
your dog's care, she's done her homework. Our concerns met and
merged the other day when we were discussing the possibility of tick
disease causing epilepsy and the difficulty of getting vets to
consider it.
"Are
you aware, that phenobarbital inhibits the effectiveness of
doxycycline?" she asked, at one point.
No,
but that was the end of my ignorance.
As
she pointed out, the effect phenobarb has on doxy could be serious.
She brought up the case of an epileptic GSD that had suddenly become
lethargic, gone off his food and seemed generally miserable.
The vet determined that the dog had anemia and attributed it to the
phenobarbital.
"Because
I've got Henry on Pb, I try to stay on top of everything it might
cause," Deb told me. "Pb can
cause anemia but it's very rare."
With
that in mind, she asked the dog's owner if she had considered tick
disease since anemia generally indicates some an underlying problem
and TBD seemed a reasonable thing to consider in this dog's case.
Yes, the vet had thought of it and put the dog on doxy.
Improvement would be seen as confirmation of a diagnosis of TBD
since it comes quickly and obviously. But the dog didn't get
better. The vet concluded that tick disease couldn't be
causing the anemia.
Deb
was rightly concerned. The conclusion that the dog didn't have
TBD might seem reasonable on the face of it, but it isn't.
Assuming
the dog's owner told her the straight of it, the vet either did not
know about the effect phenobarbital has on doxycycline or didn't
think it significant. Phenobarb makes the liver
super-efficient at getting rid of doxycycline and consequently
lowers its effectiveness. That's going to be even more
pronounced if the dog is getting the dosage of doxy recommended in
the Merck Veterinary Manual which is about half what we on Tick-L
think should be given but most vets, from my experience talking to
people, think is adequate. It's quite possible that this dog
simply wasn't getting enough doxy to cause any improvement if
the dog was
infected with Lyme or Ehrlichiosis. The phenobarb was
super-efficiently destroying an insufficient dose.
Second,
if the report Deb got is correct, this dog's vet was not aware that Babesiosis,
a common tick disease often seen in concert with Lyme or
Ehrlichiosis, does
not respond to doxycycline,
so
tick disease could not be ruled out in any case.
The
info about the destructive effect phenobarb has on doxy is important
but even more important is knowing that you have to take an active
interest in your dog's health. The more you know, the better
his chances. Don't wait to learn from experience you never
want to go through if you can help it; do your homework and
join an Internet list like Epil-k9
if your dog is seizing, where experience and knowledge are already
waiting for you.
Here
are a couple of good links to more information on phenobarbital and
the effect it has on doxycycline and other drugs.
Tick
Borne Diseases
This one is a page on tick disease as a cause of epilepsy.
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