What is chlorambucil?
Chlorambucil (brand names: Leukeran®, Chloraminophene®, Linfolysin®) is an immunosuppressive and anticancer medication used to treat certain cancers such as leukemia, lymphoma, multiple myeloma, and others. It can also be used as a supplemental treatment for some immune-mediated diseases such as inflammatory bowel disease.
Its use in cats, dogs, and horses to treat cancer and immune-mediated diseases is ‘off label’ or ‘extra label’. Many drugs are commonly prescribed for off label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions very carefully as their direction may be significantly different from those on the label.
How is chlorambucil given?
Chlorambucil is given by mouth in the form of a tablet or a specially compounded liquid. It should be given with food. Do not crush, split, or liquefy this medication on your own. Measure liquid forms extremely carefully.
Chlorambucil is considered a hazardous drug. Do not handle if you are pregnant or nursing. Always wear gloves when giving this medication, and do not reuse gloves. Do not allow the medication to come into contact with your skin, eyes, or mouth. On the day of giving this medication and for a few days afterward, handle your pet’s bodily fluids carefully and wear gloves; seal the gloves and any waste in a plastic bag before disposing in the trash. Do not allow your pet to lick your skin; if this occurs, wash the area thoroughly with soap and water.
Pregnant women should not handle this medication.
This medication can take a few weeks before full effects are noted, but side effects can occur immediately. Gradual improvements are usually noticeable after a few days.
What if I miss giving my pet the medication?
If you miss a dose, contact your veterinarian for further instructions, as this medication must be dosed very carefully.
Are there any potential side effects?
Side effects may include fur loss, or a change in the hair coat, especially in certain breeds. Serious side effects include low energy/depression, lack of appetite, vomiting, diarrhea, abnormal bleeding, bruising, infection, shortness of breath, agitation, facial twitching, seizures, or bloody diarrhea.
This moderate-acting medication should stop working in a few days, although effects can be longer in pets with liver or kidney disease.
Are there any risk factors for this medication?
Chlorambucil should not be used in pets that are allergic to it or other alkylating medications. It should not be used in pets that have bone marrow disease or active infection. Do not use in pregnant or lactating animals; use milk replacer if it is necessary to use this medication during lactation. Chlorambucil should be used with caution in pets that are susceptible to infections, such as elderly pets or those with chronic disease. Do not vaccinate your pet while using this medication unless it is recommended by your veterinarian.
Humans administering this medication are at risk for exposure. Gloves should always be worn when handling this medication. Do not reuse gloves. Do not allow this medication to come into contact with your skin, eyes, or mouth. On the day of giving this medication and for a few days afterward, handle your pet’s bodily fluids carefully and wear gloves. Seal gloves and any waste in a plastic bag before disposing in the trash. Do not allow your pet to lick your skin; if this occurs, wash the area thoroughly with soap and water. Pregnant women should not handle this medication.
Are there any drug interactions I should be aware of?
The following medications should be used with caution when given with chlorambucil: myelosuppressive agents, or vaccines. Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking.
Is there any monitoring that needs to be done with this medication?
Baseline complete blood counts, blood chemistry profiles, and urinalysis will be performed prior to your pet starting this medication. Follow up blood counts and chemistry profiles will be done every 1-3 months. Your veterinarian may monitor your pet to be sure that the medication is working.
How do I store chlorambucil?
Store chlorambucil in the refrigerator between 36°F and 46°F (2°C and 8°C) and protect from light. The tablets can be stored short-term, up to a week, in temperatures up to 86°F (30°C). Liquid formulations cannot be left outside of the refrigerator, even for only a few hours.
What should I do in case of emergency?
Any overdose, no matter how small, should be considered an emergency. If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility.
