General Description: Cyclophosphamide is a serious drug used to treat cancer and some diseases caused by an overactive immune system. It is often used in conjunction with other drugs. As this drug will suppress your pet’s natural ability to fight infection, it may be more susceptible to infections at this time.
What is this drug?
An immunosuppressive agent; an alkylating agent
Given by mouth
Reasons for prescribing:
Used in the treatment of certain types of cancer in dogs and cats (ex. bone marrow or blood cell cancers such as lymphoma)
Used in immune-mediated conditions (ex. immune-mediated hemolytic anemia)
Often used in combination with other drugs (ex. prednisone or dexamethasone)
What dogs/cats should not take this medication?
Breeding males or pregnant females
Pets with a pre-existing infection
Use with caution in pets with liver or kidney disease or has had radiation in the past
Use with caution in pets with anemia, pre-existing bone marrow suppression or those on drugs which suppress the bone marrow
If your pet has had an allergic reaction to cyclophosphamide or like products
Read and follow the label carefully.
Tablets should not be cut or crushed, but used whole.
Give the medication in the morning. Giving cyclophosphamide with food may reduce GI upset. Encourage your pet to drink water and urinate frequently.
Give the exact amount prescribed and only as often as directed. Dogs and cats usually receive this drug 4 days out of 7 for 6-8 weeks. Your veterinarian will want to perform frequent recheck appointments and blood work.
For the first couple of months, your veterinarian will monitor your pet’s blood every 1-2 weeks.
Your pet will be more susceptible to infections. Avoid situations in which your pet may be exposed to other animals.
Give this medication for as long as veterinarian directs. Do not skip doses.
If your pet is undergoing long-term therapy, do not discontinue azathioprine abruptly, as the condition may return. Your veterinarian will advise you on a dosing schedule that will taper the drug’s dose over several months.
Ideally, give the medication at the same time(s) daily.
What if a dose is missed?
If a dose is missed, give it as soon as you can. If it is time already for the next dose, skip the missed dose and go back to the normal schedule. Do not give two doses at the same time.
What to tell/ask veterinarian before giving medication?
Talk to your veterinarian about:
When will your pet need to be rechecked
What tests may need to be performed prior to and during treatment with this drug
What are the risks and benefits of using this drug
Tell your veterinarian about:
If your pet has experienced side-effects on other drugs/products
If your pet has experienced liver or kidney disease now or ever
If your pet has experienced any other medical problems or allergies now or ever
All medicines and supplements that you are giving your pet or plan to give your pet, including those you can get without a prescription. Your veterinarian may want to check that all of your pet’s medicines can be given together.
If your pet is pregnant or nursing or if you plan to breed your pet
Storage and Warnings:
Store in a tight, light resistant , childproof container in a cool, dry place at room temperature away from heat and direct sunlight.
NB. Wear gloves while handling this medication as it can cause side effects in humans. Women who are pregnant, breastfeeding or trying to conceive should not handle this drug.
For 72 hours after each dose, avoid all contact with your pet’s urine, feces, saliva or vomitus. Waste should be disposed of in a sealed plastic bag.
Keep this and all medication out of reach of children and pets.
Call your physician immediately if you accidentally take this product.
Potential side effects:
Most common side effect is bone marrow suppression. One or two weeks after starting therapy, red and white blood cell counts may drop, causing your pet to become anemic or very susceptible to infection. Monitor for unusual bleeding or bruising, abnormal breathing, fever, depression, lameness, diarrhea, change in urination or urine color. Your veterinarian will likely want to perform blood tests every few weeks to ensure blood cell counts are safe.
Most pets do not lose their hair with chemotherapy. The exceptions are wavy-coated dogs (ex. Poodles and Old English Sheepdogs). Cats often will lose their whiskers. Hair texture may get softer.
Vomiting, diarrhea and loss of appetite
Up to 30% of dogs receiving cyclophosphamide for 2 months or more develop bloody urine. Report this to your veterinarian immediately.
Cyclophosphamide use may increase the risk of bladder cancer later in your pet’s life
Unneutered males male develop sterility
Toxic to the heart at high doses
Lung damage is possible
If you notice any of these symptoms or anything else unusual, contact your veterinarian
Can this drug be given with other drugs?
Yes, but possible interactions may occur with azathioprine, digoxin, doxorubicin, methiamazole, phenobarbital, succinylcholine and thiazide diuretics
If your pet experiences any unusual reactions when taking multiple medications, contact your veterinarian
Contact your veterinarian immediately if pet receives more than the prescribed amount.
What else should I know?
Notify your veterinarian if your animal’s condition does not improve or worsens despite this treatment.
As with all prescribed medicines, cyclophosphamide should only be given to the pet for which it was prescribed. It should be given only for the condition for which it was prescribed.
This is just a summary of information about cyclophosphamide. If you have any questions or concerns about cyclophosphamide or the condition it was prescribed for, contact your veterinarian.