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Medications > Cyclophosphamide (Cytoxan) > Cyclophosphamide (Cytoxan) – Detailed Information


What is Cyclophosphamide (Cytoxan)?

Cyclophosphamide is an immunosuppressive medication (suppresses the immune system).  Cyclophosphamide is used for several different types of rheumatic disease including systemic lupus erythematosus, diseases which inflame the walls of blood vessels (vasculitis), and sometimes for rheumatoid arthritis.

How does Cyclophosphamide work?

Cyclophosphamide works by suppressing the body’s immune system.  Although this suppression can make it slightly harder for you to fight off infections, it also stabilizes the immune system if it is overactive.

How do I take Cyclophosphamide (Cytoxan)?

There are several different ways in which Cyclophosphamide can be prescribed.  Your doctor will decide which is best for you and discuss this with you.  The two main ways to take Cyclophosphamide are as follows:

  • Tablets usually taken once a day.
  • Intravenous injection usually given every 2 weeks to every month.

What is the usual dose of Cyclophosphamide (Cytoxan)?

  • The dose of Cyclophosphamide is based on your body weight.
  • Cyclophosphamide comes in 50 mg tablets.  The usual starting dose is 1.5 to 3 tablets per day (75 to 150 mg).
  • The dose of Intravenous (IV) Cyclophosphamide usually ranges from 500 to 1500 mg per infusion.  The dose will be decided by your doctor.

Who should NOT take Cyclophosphamide (Cytoxan)?

  • Patients who have had a previous reaction to Cyclophosphamide.
  • Women who are pregnant, planning on becoming pregnant, or are breast feeding.
  • Men who are planning pregnancy with their partner.
  • Some patients with diseases of the liver, kidney, or blood disorders.
  • Patients with active infections.
  • Possibly patients with a past history of cancer.

When will I start to feel the effects of Cyclophosphamide (Cytoxan)?

Cyclophosphamide does not work right away.  It will take about 6 to 12 weeks to produce an effect depending on the disease being treated.

What should I AVOID while taking Cyclophosphamide (Cytoxan)?

  • Do not get pregnant or breast feed.
  • You should discuss all vaccinations with your doctor as some vaccines are not advisable while you are taking Cyclophosphamide.
  • If you are scheduled for surgery, please tell your doctor.

Which Medications are safe to take with Cyclophosphamide (Cytoxan)?

Your rheumatologist may decide to add other medications to treat your arthritis.  Almost all medications are safe to take with Cyclophosphamide.  As an example, some of the other medications which may be safely added to Cyclophosphamide include: Acetaminophen (Tylenol), Prednisone, and NSAIDs.

What are the side-effects of Cyclophosphamide (Cytoxan)?

MORE COMMON side-effects include:

  • Nausea, vomiting, abdominal pain, and diarrhea
  • Sores in the mouth
  • Skin rashes

RARE side-effects include:

  • Hair Loss – Some patients lose their hair when taking Cyclophosphamide.  This is more common with higher doses and grows back when stopped.
  • Blood Counts – Cyclophosphamide can cause a drop in the numbers of red blood cells (which carry oxygen), white blood cells (which are needed to fight infection) and platelets (which help to stop bleeding).  The blood counts are monitored closely and changes are usually reversible when the medication is discontinued.
  • Infection – Any infections or fevers should be taken seriously and reviewed by your doctor.
  • Bladder – Cyclophosphamide can irritate the bladder which may cause pain and bleeding.  If you notice blood in the urine, notify your doctor immediately.  To reduce the risk of this happening it is important that you drink 8 to 10 glasses of water per day.
  • Fertility – Cyclophosphamide can affect fertility in both men and women.  The effect may be reversible when the medication is stopped.  If you are thinking of future pregnancies, you should discuss this very carefully with your doctor.
  • Malignancy – When used for long periods of time, Cyclophosphamide may be associated with a small increased risk of lymphoma, bladder, and skin cancer.

How can I help to minimize the side-effects of Cyclophosphamide (Cytoxan)?

  • Take your Cyclophosphamide as prescribed by your doctor, get your blood & urine tests done regularly, and attend all appointments with your doctor.
  • Take your Cyclophosphamide with food to help reduce stomach upset.
  • Drink 8 to 10 glasses of water per day to reduce the risk of bladder irritation.
  • While you are taking Cyclophosphamide, your doctor might ask you to take an antibiotic to help reduce the risk of infection.

Do I need to have regular blood tests while taking Cyclophosphamide (Cytoxan)?

YES, with the tablets you will need BLOOD & URINE TESTS EVERY TWO WEEKS TO EVERY MONTH.  This is important to make sure the Cyclophosphamide is having no harmful effects on your blood counts or bladder.  If you are receiving Intravenous (IV) Cyclophosphamide your doctor will arrange a personal schedule for your blood tests.

How do I stop the Cyclophosphamide (Cytoxan)?

Cyclophosphamide is usually weaned down slowly as your disease may “flare” after you stop the medicine.

What should I do if I miss a dose of Cyclophosphamide (Cytoxan)?

  • If you forget to take your Cyclophosphamide at the usual time but remember later on the same day, take the missed dose immediately.
  • If you forgot to take yesterday’s dose, skip yesterday’s dose and take your usual dose for today.

Is Cyclophosphamide (Cytoxan) safe in pregnancy?

  • Cyclophosphamide may cause birth defects and result in miscarriage.  You must AVOID PREGNANCY while on Cyclophosphamide.
  • All women of child bearing potential taking Cyclophosphamide must use reliable contraception.
  • If you become pregnant while taking Cyclophosphamide NOTIFY YOUR DOCTOR IMMEDIATELY.
  • You should not breast feed while taking Cyclophosphamide.