How Prednisone Helps Dogs With Cancer
How Prednisone for Dogs Works
Prednisone is a corticosteroid drug (just like prednisolone, cortisone and hydrocortisone) that is frequently used in veterinary medicine to treat several medical conditions in dogs such as allergies, inflammation, autoimmune diseases and certain types of cancers.
Prednisone is a synthetic drug (made in a laboratory in a form not naturally produced by the body) which works by imitating the effect of natural steroid hormones (corticosteroids) produced by the dog's body. Such hormones are specifically manufactured by the dog's adrenal cortex found in the adrenal glands, which sit on top of the dog's kidneys. The main steroid hormone produced by the dog's adrenal cortex is cortisol which is known as the "stress hormone."
Cortisol plays a main role in the dog's metabolism and immune system, particularly when the dog undergoes emotional or physical stress. This hormone is known to evoke the fight or flight response seen in dogs when under stress or when dogs feel threatened. Courtesy of cortisol, dogs who are under stress receive a boost of energy that spurs them into action, keeping them safe when they feel in danger or threatened by something.
Cortisol also helps control auto-immune reactions. Auto-immune disorders take place when white blood cells start attacking parts of the body as if they are foreign invaders.
This is why corticosteroids such as prednisone, prednisolone, etc. work greatly in suppressing inflammatory processes and auto-immune diseases. Once in the body, prednisone imitates the action of cortisol decreasing the symptoms of inflammatory conditions and suppressing the immune system when it's overreactive.
Prednisone as Palliative Care for Dogs With Cancer
It's unfortunate that cancer remains one of the top causes of death in dogs. Not all cancers are created the same. There are some forms of cancers where aggressive treatment involving surgery and chemo are worthy of being implemented, while there are others where these treatments are not. On top of that, some dogs may be in such an advanced state that they are inoperable and the best option is to institute palliative care.
Palliative care should not be interpreted as "giving up," but rather an attempt in maintaining a good quality of life for as long as possible. In some cases where there is advanced cancer, palliative care may provide survival times similar to those attained with aggressive treatment.
Palliative care should also not be interpreted as prolonging the inevitable. It is wrong to think of palliative care as a way to drag the dog for more days or weeks when the dog is living in sub-optimal health conditions, with a poor quality of life. At a certain point, when the dog's quality of life declines, human euthanasia should be elected so to not unnecessarily prolong the dog's suffering.
Palliative care in dogs with cancer entails nutritional support so to prevent dogs from developing nutritional deficiencies while maintaining a good appetite. Other palliative care includes pain control and other necessary steps to help maintain good physical and emotional well being. Prednisone for dog cancer may play an important role in providing palliative care.
Prednisone to Help Increase Appetite in Dogs With Cancer
Dogs with cancer have a tendency to develop what is known as cancer cachexia. Cancer cachexia is a secondary condition arising in dogs with cancer that is characterized by weight loss, loss of appetite, weakness, muscle wasting and anemia. The loss of appetite in dogs with cancer can be attributed to a variety of factors including mechanical abnormalities and iatrogenic consequences.
Mechanical abnormalities are due to the direct effect of the cancer itself. For instance, in dogs with a mouth or throat tumor, eating may be a painful ordeal. Soon, the dog starts associating the pain with food and loss of appetite often comes next. Dogs with a very enlarged spleen instead may feel satiated early because the spleen may be pressing on the stomach causing a fake sensation of fullness. Dogs with tumors affecting the digestive tract may be reluctant to eat because of mechanical obstruction, nausea or pain. Advanced-stage cancer in dogs, regardless of the body part affected, will also lead to partial or complete loss of appetite.
Iatrogenic consequences are consequences that arise from the treatment itself. For instance, dogs may develop a loss of appetite as a side effect of certain drugs used to manage the cancer, or as a result of chemotherapy or radiation which are part of the treatment plan for cancer.
The loss of appetite in dogs with cancer often starts in a subtle manner. The dog may start acting "picky." He or she may not finish up the meal as fast as before or he or she may require some coaxing. Sometimes this may be initially attributed to the dog "just getting old" and losing some sense of smell.
As the cancer progresses, at some point, the dog may start refusing food despite coaxing and trying a variety of different foods. This loss of appetite will lead to weight loss and muscle wasting over time.
The use of prednisone at this point can help make a difference, considering that one of the most common side effects of this drug is an increase in appetite. This increase of appetite is due to this drug's corticosteroid-induced euphoria which promotes appetite.
There are several other options to help increase appetite in dogs with cancer. These options include Maropitant citrate (Cerenia—Zoetis), which on top of helping dogs who are vomiting can also help with nausea, and mirtazapine. Both can be safely used together, points out Dr. Sue Ettinger, a board-certified veterinarian specializing in oncology.
Prednisone to Help Dogs With Cancer
When prednisone is administered in doses that exceed the usual levels found in a dog's body, it reduces inflammation and suppresses the immune system, which can help control inflammatory conditions and auto-immune diseases where the immune system mistakenly attacks its own tissues.
For dogs with cancer, prednisone can prove to be beneficial due to this drug's mild pain relieving effect, especially when inflammation is present. Steroids such as prednisone should not be used together with NSAIDs (non-steroidal-anti-inflammatory drugs.) Dog owners should consult with a vet when considering switching to a NSAID drug as a wash-out period is necessary.
On top of providing mild pain control, prednisone can help slow down the spread of cancer. Malignant cancer tends to spread from one body part to another, a process known as metastasis. The process is activated by an immune system flare-up where new cells depart to reach distant sites and replicate in an uncontrolled manner. When prednisone is used, this drug prevents the immune system from working properly which slows down the spread and reproduction of cancer cells.
Certain types of cancer may be managed with prednisone. Prednisone in such cases can be used as a chemotherapeutic agent or it may be combined with other stronger chemo agents for the goal of shrinking tumors.
In the case of lymphoma, prednisone is helpful because it is capable of killing lymphoma cells. Dog owners who opt not to use chemo may use prednisone as a standalone treatment for lymphoma.
The main thing to be aware of is that prednisone needs to be started only once a diagnosis is made as this drug complicates diagnostics and, on top of that, it can make chemo less effective, points out veterinary oncologist Susan Ettinger in an article on the Dog Cancer Blog.
Other forms of cancer that may benefit from prednisone are mast cell tumors, brain tumors and nasal tumors.
Dog owners are often concerned about the side effects of prednisone in dogs. Short-term side effects include increased drinking and urination, increased hunger, panting, loss of energy, onset of infections or infections getting worse, nausea or vomiting and stomach ulcers.
When prednisone is used long-term, such as for more than three to four months at high, immunosuppressive doses, there are further risks for side effects such as urinary tract infections (routine urinalysis are recommended), obesity, predisposition for diabetes, poor skin and coat condition, lowered immunity to infections and wound healing.
If your dog develops side effects from the use of prednisone report them to your vet. Your vet may attempt to adjust dosing or may prescribe another type of steroid in hopes of counteracting them.
Prednisone is a treatment for lymphoma. Alone it isn't an ideal treatment, but it can improve the quality of your dog's life over the short term. Steroids like prednisone have some toxic effects towards the cells that are inappropriately multiplying in your dog. This effect doesn't kill all the cancer cells and it won't work forever, but it may make your dog feel better.— Dr. Shadwick, veterinarian
- DVM360: Treating cancer pain in dogs and cats
- DVM360: Extending quality of life in cancer patients
- Dog Cancer Blog: Common Cancer Mistake: Starting Your Dog with Lymphoma on Prednisone Too Soon
- VCA Animal Hospital: Steroid Treatment - Long-Term Effects in Dogs
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© 2018 Adrienne Janet Farricelli