首页 > 分享 > 【小动物化疗（Chemotherapy）的知识全集包括常见化疗药物副作用】

【小动物化疗（Chemotherapy）的知识全集包括常见化疗药物副作用】

萌宠菠菠乐园
2024-12-31 05:32

　　作者：David Vail 本文章为全部为英文，仅供学习和帮助小动物健康使用，不要用于商业用途。

　　What you should know when your pet needs chemotherapy

　　Cancer is often a difficult disease to control and frequently requires a variety of treatments. Similar to cancer treatment in people, surgery, radiation and chemotherapy are often used alone or in combination to control cancer in pets. Chemotherapy is frequently used to treat cancer that has spread to other parts of the body, to treat cancer that is not amendable to surgery/ radiation alone or when it may enhance the effectiveness of these treatments.

　　What is the goal of chemotherapy?The goal of chemotherapy is to control or eliminate the cancer while still providing the highest quality of life to your pet companion. Chemotherapy drugs may not cure cancer but rather control the cancer by killing cells and slowing the progression of the tumor. A period of time when the cancer is controlled is referred to as a remission time. Remission time varies with different types of cancer and also with different types of treatment options.

　　What is chemotherapy?Chemotherapy is drug therapy designed to kill or slow the growth of cancers. Many of the drugs used to treat cancer are derived from natural substances such as plants, trees or even bacteria and are often the same drugs used in people.

　　How does chemotherapy work?Cancer can generally be defined as a rapid, uncontrolled growth of cells. Because chemotherapy tends to circulate to all parts of the body, it is used to provide a total body effect (a ‘systemic’ effect) and kill cancer cells that may be widespread. In many cases, a combination of different chemotherapy drugs is the most effective way to kill cancer cells and so for some cancer types, we will recommend more than one drug as part of the treatment.

　　How is chemotherapy given?Chemotherapy drugs can come in different forms: pills, capsules, oral or injectable liquids. Some of them must be given intravenously (IV), others may be given under the skin (subcutaneously) or into a muscle. In rare cases the drug may be injected directly into the tumor itself.

　　· IV drugs: such as vincristine or doxorubicin, an intravenous catheter must be placed for safe administration of the drug directly into a vein. After administration, the catheter is removed and a light bandage is placed. The “band-aid” can be removed 1-2 hours after the drug is administered. If your pet licks at the injection site longer than a day or if the site turns red or becomes painful, this may be a sign that some drug may have leaked outside the vein. This can become a serious problem and you should contact your veterinarian immediately since this may be a serious complication.

　　· Intramuscular or subcutaneously injected drugs: These are drugs given by injection either into a muscle or just under the skin and are slowly absorbed into the blood stream.

　　· Oral drugs: oral drugs are administered either in the hospital or by you at home. It is important that your pet receive all medications as prescribed and that the pills or capsules are not crushed. It is sometimes helpful to coat the pills with butter, peanut butter or cream cheese to cover the bitter taste of the medicine. Edible pill pockets may also be helpful. If you are administering an oral chemotherapeutic drug, you will be given special chemotherapy gloves to wear while you handle these pills. When you are finished giving the pills, wash your hands to remove any medication residue from your skin.

　　How often is chemotherapy given?Some drugs are given daily or every other day, others weekly and some only every 2-3 weeks. Your time commitment will depend on the chemotherapy drug protocol you choose to treat your pet with.

　　What is a chemotherapy drug protocol?The word protocol refers to a set regime of drug(s) given in a specific time frame. This may incorporate one or multiple drugs.

　　How long will my pet be on chemotherapy?The length of time and the frequency of drug administration will depend on the type of cancer being treated and how well the therapy is tolerated by the patient. Chemotherapy may be used for the life of the pet to control the disease. If chemo is being used to control small amounts of tumor cells after surgery or radiation, drugs will be given for a few weeks or months and then discontinued.

　　What happens when chemotherapy no longer controls the cancer?Cancers are often initially very sensitive to chemotherapy drugs and shrink tumors dramatically, often within days or weeks. Unfortunately, the cancer may return weeks, months or even years later despite effective drug treatment. In such cases, the cancer cells have become resistant to the chemo drugs in a similar way bacteria become resistant to antibiotic therapy. When resistance to one drug occurs, we can often use another drug to achieve the desired effect. In some cases, cancer develops resistance to all drugs. At this point, your pet’s veterinarian will discuss with you other treatment options as well as ways to keep your pet comfortable for the remainder of his/her life.

　　May my pet receive vaccinations while on chemotherapy?Recent research indicates it is safe to give your pet vaccines while they are receiving chemotherapy, but the response to the vaccine may not be optimal. We recommend waiting 2 months after chemotherapy to resume a vaccination schedule.

　　WILL YOUR PET EXPERIENCE SIDE EFFECTS WHILE ON CHEMOTHERAPY?

　　The highest quality of life for your pet is our goal, but to be effective in controlling a serious disease like cancer, chemotherapy drugs are very powerful. Veterinary oncologists try to choose drug dosages and combinations of drugs that cause the fewest side effects while giving the best treatment advantage possible for your pet. Fortunately, pets tend not to experience as many side effects as humans going through chemotherapy do. As mentioned above, chemotherapy tends to kill rapidly dividing cells, like cancer cells and interferes with their ability to grow and multiply. There are, however, normal cells in the body that are also rapidly dividing and may also be damaged by chemotherapy (example, the bone marrow that produces normal white blood cells, the lining of the intestinal tract, and some hair follicles) and therefore chemotherapy has the potential to cause side-effects in some pets undergoing treatment. In general, the likelihood of your pet having a serious side-effect (something requiring veterinary intervention or hospitalization) is approximately 3 – 5%. We now have available several effective drugs to help prevent or treat the side-effects and we strive to keep the likelihood of your dog or cat experiencing discomfort to a minimum.

　　Please observe your pet closely during treatment. Please fell free to phone us at any time your companion appears to feel ill or if you have a question regarding the drugs used, the drugs sent home with you, or if any problems in your pet arise that concern you.

　　The following is a list of theGENERALside effects that can occur following most forms of chemotherapy in dogs and cats:

　　Hair loss:Hair loss (alopecia), common in humans, is seen mainly with the non-shedding breeds who have continually growing hair coats like people (example, poodle, shih tzu, cocker spaniel, etc.). Most ‘shedding’ breeds like labs, retrievers, and shepherds do not lose significant amounts of hair. Cats generally do not lose body hair, but often lose their whiskers. Chemotherapy will slow the re-growth of hair in all pets receiving chemotherapy so body clipping should be adjusted accordingly.

　　Gastrointestinal (stomach and intestine) side effects:These potential side effects include nausea, vomiting, diarrhea- all of which are usually easily prevented or controlled with medications/ diet change; we may be sending home anti-nausea and anti-diarrhea medication with you after chemotherapy. These side effects, if they occur, usually develop 2 – 5 days after chemotherapy and only last for a few days. If your dog or cat experiences nausea, vomiting, or loss of appetite, please call us for further treatment or suggestions. Vomiting once or twice without any other signs or fever should be reported to us, but does not usually require further treatment. Withdrawing food and water for a few hours may be helpful. Water should be reintroduced at first and if your pet can hold this down, then offer a bland diet (cottage cheese, white rice) in small, frequent amounts. Frequent vomiting may require fluid therapy be delivered by a veterinarian or the addition of anti-vomiting drugs. Diarrhea without vomiting or fever can usually be managed with a bland diet also until stools are normal and then gradually switching back to a regular dog food.

　　Low white blood cell counts and/or fever:A common side effect with all chemo patients is a decrease in the white blood cell count that is usually maximum at 1 week after treatment. For most dogs and cats, the low white blood cell count is ‘silent’; that is, it is not low enough to result in infection, sickness or fever and the white blood cell count returns to normal in a few days. Less commonly, the white count gets low enough to result in your pet feeling lethargic and makes them more susceptible to contracting fever and infections. If you companion appears ill, and you feel comfortable doing so, please take his/her rectal temperature and call us if your are concerned or if the temperature is elevated above 102.8 degrees. At UW, we routinely check the blood cell counts before every chemotherapy treatment as well as 1 week after each treatment to evaluate how the pet’s body is managing. If the white blood cell count is very low, or if fever is present, the addition of antibiotics may be indicated. If the white blood cell count gets very low it is also advisable to avoid places where your pet would be exposed to possible infections (public areas where many dogs pass through -parks, grooming facilities and boarding kennels).

　　Allergic reactions:Dogs and cats can have allergic reactions to any drug and chemotherapy is no exception. Most allergic reactions occur within 1 – 3 hours after giving a drug and are readily treated with antihistamines or corticosteroids by your veterinarian. Signs of an allergic reaction include swelling of the face, hives, rash, vomiting, and rarely, difficulty breathing. If you notice any of these signs, please call us.

　　Perivascular necrosis (tissue damage around a vein where chemotherapy is given):Some of the drugs that are given intravenously (IV) can cause tissue damage if a small amount were to leak outside of the vein. This is rare as we are very careful with catheter placement and watch every patient closely while giving their chemotherapy. However, in rare events, if small amounts of drug leak outside of the vein, redness, swelling, pain and lameness can occur in the leg in which the drug was given. This can become serious if untreated and if you notice any of these signs please call us. We keep a record of the vein used for each treatment and can act quickly if we suspect a problem.

　　COMMONLY USED CHEMOTHERAPY DRUGS AND SIDE-EFFECTS SPECIFIC TO THEIR USE:

　　Doxorubicin (Adriamycin®)– administered IV every 2-3 weeks; side effects include those listed above under general side effectsandpotential damage to the heart muscle in a small percentage of patients. It is usually safe in most dogs but the risk of heart disease increases with the number of times the drug is given. We may recommend performing a heart function exam (echocardiogram) before starting this drug in some cases or if your dog has received several doses. The dose we use is generally below the known level that causes heart damage in most dogs and less than 5% of all pets develop heart problems with this drug. Doxorubicin generally is safe for the heart in cats, but can damage the kidneys in cats so we will recommend monitoring of kidney function by blood tests and urine tests in cats.

　　Carboplatin (Paraplatin®)– administered IV every 2-4 weeks; side effects can include those listed above under general side effects, but this drug is generally easier on the stomach and intestines. Deafness has been noted in humans, but is rare in pets.

　　Cisplatin (Platinol®)– administered IV every 3 weeks; side effects include those listed above under general side effects, but most importantly this drug can cause kidney damage. To avoid or minimize damage, blood work before the administration of the drug will alert your clinician if the kidneys are weak. If the kidneys have normal functioning values, your pet will receive IV fluids several hours before and after the administration of the cisplatin to flush the kidneys. Deafness is also a rare side effect of this drug.

　　L-Asparaginase (Elspar)– administered as an injection just under the skin; the most common side effect is an acute allergic reaction. After administration of this drug, either you or a hospital staff person will watch your pet for 60 minutes to observe for signs of allergic reaction. If you see any of these signs after you take your pet home, contact a doctor or nurse in the Clinical Oncology Service at UW or at your local emergency veterinary clinic.

　　Mitoxantrone (Novantrone®)– administered IV every 3 weeks; side effects include those listed above under general side effects.

　　Vincristine (Oncovin®)– administered IV every 1-3 weeks; side effects include those listed above under general side effects.

　　Vinblastine (Velban®)– administered IV every 1-3 weeks; side effects include those listed above under general side effects.

　　Cyclophosphamide (Cytoxan®)– administered by mouth or by injection; side effects include those listed above under general side effectsandblood in the urine (hematuria). If you notice your pet is straining to urinate or if you see blood in the urine, stop administering the drug and call your pet’s veterinarian.

　　Leukeran (Chlorambucil®)– administered by mouth daily or every 2 weeks; side effects include low white blood cell counts

　　Lomustine (CCNU®)– administered by mouth every 2-3 weeks; side effects include those listed above under general side effects as well as the potential to damage the liver. We will perform blood tests from time to time to look for liver problems.

　　Steroids (prednisone, prednisolone or triamcinolone)– administered by mouth daily to every other day; side effects include increased appetite, increased water consumption, increased urination, panting and a pot-bellied appearance. Cats have lower incidence of these side effects.

　　Melphalan (Alkeran)– administered by mouth every day or every 2 weeks; most common side effect is a low white blood cell count.

　　SAFE HANDLING OF CHEMOTHERAPY AND SAFE CONTACT WITH YOUR PET AT HOME AFTER CHEMOTHERAPY: We will provide you with a separate handout on this topic. Please read it carefully and ask your veterinarian any questions you may have regarding this issue.

　　If you have any questions or if any problems arise during your pets chemotherapy, please do not hesitate to contact your veterinarian.

　　作者：David Vail 本文章为全部为英文，仅供学习和帮助小动物健康使用，不要用于商业用途。

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