Updated February 2023

What is cyclophosphamide?

Download button - information sheetCyclophosphamide is a medication used to treat severe inflammatory diseases (diseases which may affect kidneys, blood vessels, joints, muscles, skin, gut or eyes). This can include complicated lupus (also known as SLE), vasculitis, uveitis and scleroderma. It is also used to treat certain cancers.

Cyclophosphamide is a medication that works by suppressing your immune system. It reduces the damage done by inflammation, rather than just reducing pain.

Important things to remember

  • You must see your rheumatologist regularly to make sure the treatment is working and check for possible side effects.
  • You should have regular blood tests as suggested by your rheumatologist.
  • If you are worried about any side effects, you should contact your rheumatologist as soon as possible.
  • If you stop cyclophosphamide for any reason, you must contact your rheumatologist.

How will it help?

Cyclophosphamide is a medication that works slowly. You can expect your child to gradually start feeling better, but it might take weeks to months.

How is cyclophosphamide given?

Cyclophosphamide is given via a vein as an infusion, or as an oral tablet.

When should it be given?

Tablets: Daily
Infusion: Approximately once a month for up to six months.

What is the dose?

This depends on the weight of your child. When the disease is under control, other medications may be started. The dose of cyclophosphamide may then be reduced or stopped.

How long will it be used for?

People may stay on cyclophosphamide for long periods (several years) to help keep their disease under control. The dose is usually reduced after the first six months.

Are there any side effects?

Cyclophosphamide is usually very effective in improving your child’s condition, but as with all medications side effects can occur. Some are common, and some are rare. Most people don’t have any problems when they take cyclophosphamide. You must have regular blood tests while you are on cyclophosphamide.

Most common side effects


Nausea (feeling sick) vomiting, loss of appetite & diarrhoea

  • Dose alteration
  • Anti-emetics (anti-sickness medication)

Hair loss

  • Usually grows back when cyclophosphamide is stopped

Mouth ulcers Sore gums Sore throat

  • Talk to your doctor as there are a range of treatments

Disturbance in the blood counts (change in blood tests results)

  • Usually returns to normal when cyclophosphamide is stopped


Rare side effects


Upset liver function

Cystitis (inflammation of the lining of the bladder)

Heart failure

  • Usually returns to normal if azathioprine dose reduced or stopped
  • Drink plenty of fluids to try to avoid this

  • Usually returns to normal if cyclophosphamide dose is reduced or stopped


Things you need to know when your child is taking this medication

What to do if your child is sick
Don’t give cyclophosphamide if your child:

  • Has a high fever
  • Has had vomiting/ diarrhoea
  • Has been in contact with chickenpox or shingles
  • Is sick and you’re not sure why

If you’re not sure, talk to your doctor, and get your child checked if necessary before giving the cyclophosphamide.

Cyclophosphamide can interact with many other medications. Talk to your doctor before your child takes any prescription medications, natural medications and medications that you can buy over the counter.

Most immunisations are safe to have (flu vaccine, cervical cancer vaccine, killed polio vaccine (IPV) etc) when taking this medication.
Live virus vaccines (such as mumps, measles, rubella (MMR), polio (OPV)), varicella (chicken pox) and some travel vaccines should not be used when taking cyclophosphamide.

Patients on cyclophosphamide are at increased risk of infection, because of immune suppression. Cyclophosphamide can make chickenpox infections more serious. A blood test can be done to see if your child is already immune to the virus. If your child is in contact with chickenpox or shingles, call your doctor.

Cyclophosphamide and alcohol are both broken down by the liver. Drinking alcohol while you are on this medication can put extra strain on the liver. It is not known how much is safe, so it is suggested that anyone on cyclophosphamide should avoid drinking alcohol.

There is an increased risk of developing different types of cancer with cyclophosphamide even many years later.  

Sexual health and pregnancy 
Being pregnant while you are taking cyclophosphamide, it can be very bad for the baby. Patients who are sexually active, should use effective contraception to avoid getting pregnant. Women on cyclophosphamide may stop getting their periods but they usually return after the drug is stopped. Having been on cyclophosphamide may affect fertility for the future. Your doctor will discuss this before the medication is started.

Myths and misconceptions
You may hear a lot of different information about cyclophosphamide from friends, pharmacists or people that you know. If you are worried about anything, please talk to your child’s doctor or nurse. If your child is taking cyclophosphamide they should see their paediatric rheumatologist regularly to make sure the treatment is working and to minimise any possible side effects.