Cyclophosphamide for Dogs

Cyclophosphamide has been created for use in humans, but it is also used in veterinary medicine. The drug is marketed as Cytoxan or Neosar and will be applied in dogs with cancerous tumors and autoimmune diseases.  Cyclophosphamide is a substance that will suppress the activity of the immune system and prevent the development of cells. The treatment may be applied as a short or long term treatment.

Cyclophosphamide for Canines

Cyclophosphamide is a nitrogen mustard based agent medication and will have 2 main effects:

  • Suppresses the immune system, being a recommended course of treatment for dogs that have an abnormal activity of the immune system (i.e. lupus or other autoimmune diseases)
  • Interferes with the development of cells

The drug is only available through prescription. Even if cyclophosphamide is not FDA approved for use in dogs, it can be administered as an extra label drug.

When Is Cyclophosphamide Recommended

Most commonly, cyclophosphamide is used in the management of cancers and malignant tumors. This is due to the fact that the ingredients in the drug will stop the development of these malignant cells and this can delay the onset of the following stage of the cancer; the treatment may be used as soon as the cancer is discovered and will be able to halt the disease until the vet performs other tests and decides if surgery is till an option.

In other cases, cyclophosphamide will be used for immune system diseases such as lupus or hemolytic anemia. This is not the first choice treatment, as typically these conditions are managed with the use of cortisone, but can be used if prednisone or prednisolone fail to suppress the immune system or cannot be administered due to kidney or liver conditions. In some cases, cyclophosphamide is used in conjunction with cortisone, on alternative days.

Side Effects of Cyclophosphamide

Cyclophosphamide can have side effects, which may include:

  • Lack of appetite
  • Diarrhea and vomiting, especially during the first weeks of administration, while the dog’s body gets used to the drug compounds
  • Bladder problems
  • Reduced white cell production
  • Modified blood test results
  • Kidney damage

Cyclophosphamide Contraindications

The drug shouldn’t be used in dogs with:

  • Bone marrow problems or a low white and red blood cell count
  • Sensitivity to cyclophosphamide
  • Severe infections (which need to be treated prior to starting the cure with cyclophosphamide)
  • Kidney issues
  • Advanced liver damage

Cyclophosphamide Dosage

The dosage of cyclophosphamide will be established by the vet and should be followed strictly. You shouldn’t discontinue the administration of these drugs without consulting the vet and you shouldn’t change the dosage.

Typically, the dosage will be higher for dogs that have an immune system disorder.

The treatment may be administered for a shorter period of time (i.e. in the case of cancer) or may be a long term treatment in dogs that have immune system diseases.