Although Procrit was made for people, vets also use it in cats suffering from anemia or kidney failure. Erythropoietin is the name of the actual hormone, which cause the body's bone marrow to create red blood cells. It's also marketed under the names Epogen and Eprex.
Since Procrit is manufactured only for human use, your vet is using it off-label, which is acceptable under U.S. Food and Drug Administration regulations. However, this means the drug is a copy of the human. not feline, version of erythropoetin. While it's generally effective in cats, some felines develop antibodies against it. Often the reaction is fairly mild, so vets continue to use the medication because it's so useful in red blood cell production. Your vet will monitor Kitty closely while he's on Procrit.
Kidney failure occurs fairly often in older cats. Since most erythropoetin is produced in the kidneys, along with a lesser amount in the liver, loss of kidney function means low erythropoetin production. The subsequent lack of red blood cells results in anemia. Giving Kitty Procrit ideally brings his red blood cell count back into normal range. If Kitty is severely anemic, he might require a blood transfusion before he can receive Procrit.
Cats receiving Procrit might become tired and weak and lose their appetites. If Kitty is being treated for kidney disease, your vet will make sure that he isn't suffering from high blood pressure—since the kidneys regulate blood pressure—before prescribing Procrit. If Kitty does have high blood pressure, or hypertension, she might prescribe a medication to lower it if putting him on Procrit. Cats whose bodies put up a full-scale alert at the supposed invader can suffer serious side effects, including cessation of the production of natural erythropoetin and severe compromising of the immune system. Even if your cat doesn't exhibit side effects, Procrit often loses its effectiveness against anemia over time.
Cats receive Procit via injection. Since Kitty probably needs injections three or more times a week, your vet will teach you how to give these subcutaneous injections yourself so you can give him injections at home. Your vet will also prescribe an iron supplement, generally in tablet form. You'll bring Kitty to the vet weekly for blood testing until his red blood cell count comes back to normal. At that point you might need to inject him only once a week, or however often your vet recommends.
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