a) How, exactly, is prednisone used as a treatment for leukemia? What does it do, how does it work, and what is the benefit in this specific situation?
b) (if #1 doesn’t answer this) As an immunosuppressant drug, how does it not make the body more prone to infection during chemotherapy?
I’m not sure if I’m misunderstanding the idea of prednisone, or the basics of leukemia. Guide me, dopers.
Generally speaking there are two types of white blood cells - neutrophils and lymphocytes. Prednisone has the ability to destroy (or at least severely limit) lymphocytes. Hence, leukemias that result from uncontrolled growth of lymphocytes can be treated with prednisione (i.e. malignant lymphocytes tend to retain their susceptibility to prednisone).
Your intuition is correct - use of prednisione does lead to a more immunosuppressed state. However, by helping control the malignant lympocytes in certain leukemias, prednisone permits the normal white blood cells to reconstitute themselves and that will tend to restore normal immune function.
Peope who take prednisone for other reasons, say for arthritis, may indeed become immunosuppressed and thus susceptible to all sorts of nasty infections (typically viral, fungal, parasitic, and TB).
Absolutely! In fact, prednisone (or any one of a number similar drugs) is found in virtually all lymphoma treatment regimens.
Moreover, since prednisone is pretty easy is to take, without the nasty side effects of most chemotherapeutic agents, it is sometimes used strictly for symptom relief in lymphoma and not in an attempt at cure. In other words, even for people who have an incurable lymphoma, or who have elected to forgo treatment, prednisone may have a role to play.
(For those who don’t know, lymphoma is a cancer of the cells of the lymph “glands”. So, it’s quite similar to a leukemia of the lymphocyte type of white blood cells.)
The problem that is commonly seen in veterinary medicine is where a relatively young, healthy dog is diagnosed with lymphoma. Although relatively simple, single agent (Doxorubricin) chemotherapy can create a long lasting remission, either the client or the veterinarian decides to treat palliatively with prednisone.
When the animal responds nicely, the owner then decides that maybe it would be wise to explore chemo, however the prior round of prednisone often makes the use of a chemotherapeutic regime impossible.
This is quite ironic. Our four-year-old lab-springer mix developed a fulminant, highly aggressive lymphoma. She was so sick, so soon, that chemo really didn’t seem to be an option. On my own, then, I gave her dexamethasone (basically just a souped up version of prednisone). In 24 hours she went from being almost moribund to bringing me her ball to throw to her! Alas, this state didn’t last very long at all - she soon slipped back into truly horrible shape and had to be put down within a week.
Why is my doctor giving out prednisone shots like candy for anyone who presents with sinus infection, upper-respiratory nastiness, etc? Does it help?
A separate antibiotic is given, as well. Just seems like the antibiotic and prednisone may be working against each other. Or else the antibiotics are necessary because the patient’s body is less likely to fight off the infection on its own after having received prednisone.
Canine lymphoma varies incredibly on presentation. I’ve had dogs present moribund, while others are diagnosed when the dog presents for something else entirely. Right now I have 4 dogs I am treating who have gone through 3 rounds of doxorubricin and are free of disease. For many reasons though, the vast majority of cases I see are euthanized at the time of diagnosis.
Corticosteroids (IMHO) are over used in general, but dosage is important to consider. At a very low dose, prednisone is antipruritic. At a higher dose it is antiinflammatory. As the dosage increases further it is immunosuppresant.
To be clear, I should say that it is only with long term use (months to years) that prednisone typically leads to enough immunosuppression such that unusual infections may develop (so-called opportunistic infections). Short term treatment is relatively benign but not without risk.
In terms of short term use for things like sinusitis, prednisone is very effective at reducing inflammation. Indeed, it is the inflammation, not the infection per se of conditions such as sinusitis, that causes them to be symptomatic.