How does this medication work? What will it do for me?

Cyclophosphamide belongs to the group of cancer-fighting medications known as antineoplastics, and specifically to the group of antineoplastics known as alkylating agents. Cyclophosphamide prevents the growth of cancer cells by interfering with the genetic material DNA, which is necessary for reproduction of cells. Because cancer cells reproduce more quickly than normal cells, they are targeted by the medication.

Cyclophosphamide is used to treat many types of cancer including cancers of the blood (e.g., leukemia, lymphoma), Hodgkin's disease, small cell lung cancer, multiple myeloma, neuroblastoma, retinoblastoma, and cancers of the soft tissues (including muscles).

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. As well, some forms of this medication may not be used for all of the conditions discussed here. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

What form(s) does this medication come in?

Injection

Each vial contains cyclophosphamide 200, 500, 1000, or 2000 mg. Nonmedicinal ingredients: none.

Tablets

25 mg
Each round, deeply biconvex, white to off-white, sugar-coated tablet contains 26.7 mg of cyclophosphamide monohydrate equivalent to 25 mg anhydrous cyclophosphamide. Nonmedicinal ingredients: calcium carbonate, cellulose, dibasic calcium phosphate, gelatin, glycerin, lactose, magnesium stearate, polyethylene glycol, polysorbate, povidone, silicon dioxide, starch (corn), sucrose, talc, titanium dioxide, and wax.

50 mg
Each round, deeply biconvex, off-white, sugar-coated tablet contains 53.5 mg cyclophosphamide monohydrate equivalent to 50 mg anhydrous cyclophosphamide. Nonmedicinal ingredients: calcium carbonate, cellulose, dibasic calcium phosphate, gelatin, glycerin, lactose, magnesium stearate, polyethylene glycol, polysorbate, povidone, silicon dioxide, starch (corn), sucrose, talc, titanium dioxide, and wax.

How should I use this medication?

The recommended dose of cyclophosphamide varies widely according to the specific condition being treated, the response to therapy, and other medications being used. The dose is based on body weight. It is available as an intravenous (into the vein) injection and as an oral tablet.

The intravenous form is injected into a specially prepared site on the skin. The dosing regimen for this medication varies widely. Tablets are sometimes taken on a daily basis in smaller doses, but can also be given in larger doses for a few days at a time with 2- to 4-week intervals between doses.

The intravenous form of the medication is sometimes administered twice a week, but larger doses may be given every 3 to 4 weeks depending on the condition being treated. The intravenous form of cyclophosphamide is always given under the supervision of a doctor. Very careful handling of this medication is required. It is always given in a hospital or similar setting with access to sterile equipment for preparation.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor.

Cyclophosphamide is excreted in urine. Your bladder will become irritated if the urine containing cyclophosphamide stays inside it for too long. It is therefore important that you drink extra fluids while taking cyclophosphamide so that extra urine is passed. The bladder should be emptied frequently so that the kidneys continue to work well. You may need to drink up to 7 to 12 cups of fluid a day.

Cyclophosphamide tablets must be taken exactly as directed by your doctor. They are usually taken first thing in the morning to reduce the risk of bladder problems. Talk with your doctor about the best dosing schedule for your circumstances. Stomach upset can be decreased by taking the medication with food. This medication may cause nausea, vomiting and loss of appetite, but it is important that you continue to use the medicine. Do not stop taking the medicine without talking with your doctor. If you vomit shortly after taking a dose of medicine, call your doctor for instructions on whether to skip that dose or to take another dose.

As well as interfering with the genetic material DNA of cancer cells, cyclophosphamide can interfere with some of your normal cells. This can cause a number of side effects such as hair loss and mouth sores. Keep track of any side effects and report them to your doctor as suggested in the section "What side effects are possible with this medication?"

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Do not use this medication if you:

  • are allergic to cyclophosphamide or any ingredients of this medication
  • are breast-feeding
  • have liver or kidney dysfunction, inflammation of the bladder (cystitis) or urinary outflow obstructions
  • have low platelet counts
  • have severe low white blood cell counts
  • have varicella-zoster infections

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • darkening of skin and fingernails
  • diarrhea
  • flushing or redness of face
  • headache
  • increased sweating
  • loss of appetite
  • nausea and vomiting
  • rash, hives, or itching swollen lips
  • stomach pain
  • temporary loss of hair (returns after treatments end, although texture or colour may change)

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • black, tarry stools
  • blood in stools
  • cough or hoarseness
  • fever or chills
  • frequent urination
  • lower back or side pain
  • missed menstrual periods
  • painful or difficult urination
  • pinpoint red spots on skin
  • redness, swelling, or pain at site of injection
  • sores in mouth and on lips
  • sudden shortness of breath
  • unusual bleeding or bruising
  • unusual thirst
  • yellow eyes or skin

Stop taking the medication and seek immediate medical attention if any of the following occur:

  • black, tarry stools or blood in stools
  • blood in urine
  • confusion or agitation
  • fast or irregular heartbeat
  • fever or chills with cough or hoarseness
  • frequent urination
  • hallucinations (seeing things that are not true or real)
  • lower back or side pain with fever or chills
  • painful urination or burning upon urination
  • seizures
  • signs of allergic reaction (swelling of the mouth or tongue, difficulty breathing)
  • unusual tiredness

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Pregnancy: Cyclophosphamide may be harmful if used during pregnancy. It is best for both men and women to use birth control while being treated with this drug. Tell the doctor immediately if you become pregnant while using this drug. It should not be used during pregnancy unless the benefits clearly outweigh the risks.

Breast-feeding: Cyclophosphamide passes into breast milk. Women should not breast-feed while receiving cyclophosphamide treatment.

What other drugs could interact with this medication?

There may be an interaction between cyclophosphamide and any of the following:

  • alcohol
  • amphotericin B
  • azathioprine
  • benzodiazepine
  • cocaine
  • colchicine
  • chlorambucil
  • corticosteroids
  • cyclosporine
  • cytarabine
  • flucytosine
  • ganciclovir
  • glyburide
  • grapefruit juice
  • interferon
  • methotrexate
  • NSAIDs (e.g. indomethacin)
  • other cancer drugs
  • phenobarbital
  • phenytoin
  • plicamycin
  • probenecid
  • sulfinpyrazone
  • zidovudine

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.