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Pre-Surgical Information
Spaying or neutering your pet is a big step! There is a lot to consider
when we are planning your pet’s surgery. Here is some information to help
you make wise decisions.
Click here . . .
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Special LibraryOur Special Library
is a collection of informative articles on a variety of health topics.
Click here . . .
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Discharge InstructionsClick here for
information on how to care for your pet at home.
Click here . . .
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 Epogen
for Cats
One of the many things the kidneys do is to regulate how
many red blood cells are circulating. This makes
sense, because the kidneys filter the entire blood
volume many times a day and are in an excellent position
to keep track of stuff like that. When the kidneys
decide that there needs to be more red blood cells, they
release a hormone called erythropoeitin. The
erythropoeitin is carried by the blood, and when the
bone marrow detects it, the marrow produces more red
blood cells.
When the kidneys fail, one of the functions that fails
is the production of erythropoeitin. With low
levels of this hormone in circulation, the patient's red
blood cell count drops to abnormally low levels.
This is called anemia.
We measure the number of red blood cells in two ways.
The simplest is by a lab value called Packed Cell
Volume, or PCV. Simply put, blood is made up of
two things, the cells, and the fluid. Normally,
about 40% of the blood is cells and 60% is fluid.
To measure this, we put blood in a thin tube, plug one
end, and spin it in a centrifuge. Spinning the
tube simulates much higher gravity, and the heavier
cells settle to the bottom
 quickly.
We then simply measure the relative proportions of
cells to fluid.
When the number of red blood cells goes down, the PCV
drops. Normally, cats run about 30 to 45.
When cats get down to below 20, it is time to consider
starting treatment.
Treatment consists of giving extra erythropoetin.
There is product called Epogen or Procrit that is made
for humans. It is pure recombinant human
erthropoetin, which means that it is an exact copy of
the human version of erythropoetin. It is made by
transplanting the human gene into a bacterium.
Although cat erythropoetin is slightly different than
the human version, it is apparently close enough,
because it works to stimulate cat red blood cell
production.
However, because human erythropoetin is slightly
different than cat erythropoetin, some cats will treat
it as a foreign invader, just like a transplanted
kidney, and make antibodies against it. Some
studies report that this happens in as many as 30% of
cats. At best, this renders further treatment
futile. At worst, it can rarely cause an
irreversible worsening of the anemia problem, even
resulting in death.
Most clinicians believe that it is better to treat
severly anemic cats than to not treat despite the risks.
Although reactions to erythropoetin do seem to happen in
as many as 30% of the cats we treat, the reaction is
often mild, and with appropriate monitoring no lasting
harm is done. It is important to realize, however,
that a real, albeit small, risk of serious adverse
events exists.
The latest treatment protocol calls for injections once
a week. At the time of the first injection,
supplementary vitamins and minerals are given as well,
and are repeated once a month as needed. The PCV
must be checked weekly at each injection to watch for
the development of adverse reactions. Once the PCV
reaches 28 or so, we usually stop injections and monitor
PCV once a month, giving an injection whenever the PCV
drops again.
Erythropoetin comes in a vial that holds 2000 units.
We give about 50 units per pound each dose, so most cats
get about 250 units (for 5 pounds of bodyweight) to 500
units (for 10 pounds of bodyweight), making a bottle
last for 4 to 8 doses. We are unable to sell the drug
by-the-dose, so a client must buy a whole vial at a time
for their cat. A vial costs about $80. It
costs around $15 to $25 per visit for a PCV measurement,
vitamin injection if needed, and the erythropoetin
injection, not including the cost of the
erythropoetin.
Many cats in renal failure have been helped by
erythropoetin injection. Used cautiously and
monitored well, it can safely provide increased vitality
and energy for anemic cats. |
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