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What does it do?

Leflunomide is used to treat some types of arthritis. It may be used alone or with other medicines.

How should you take it?

Take leflunomide regularly as directed with a glass of water. Do not break or crush the tablets.

What if you forget a dose?

Take the missed dose as soon as possible. If it is close to the time for your next dose, skip the missed dose and carry on as normal. Do not take two doses at the same time.

Can you take other medicines?

Tell your pharmacist or doctor about all medicines or treatments that you may be taking, including vitamins, herbal products (e.g. activated charcoal, St John's wort) or recreational drugs.

What side effects might you notice?

Side EffectsRecommended action

Severe skin rash, skin peeling or blisters

Stop taking and see your doctor immediately

Reduced number of blood cells that fight infections or help your blood to clot - symptoms include: fever, chills, sore throat or generally feeling unwell, or easy or unusual bruising or bleeding

Symptoms of liver problems including: yellow skin or eyes, itching, dark urine, pale bowel motions, abdominal pain

Short of breath, persistent dry cough

Tell your doctor immediately

Pain, sores, or redness in mouth or on lips

Tell your doctor

Hair loss or thinning


Joint or muscle aches or pains, numbness or tingling of the fingers or toes

Diarrhoea, nausea, loss of appetite, weight loss

Tell your doctor if troublesome

If you notice any other effects, discuss them with your doctor or pharmacist.

Other information:

  • Tell your doctor if you have liver, lung or blood pressure problems.
  • Tell your doctor if you have a long-term infection e.g. tuberculosis, HIV or hepatitis B or C.
  • Leflunomide must not be used if you are pregnant, planning to become pregnant or breastfeeding. Women should use reliable contraception while taking leflunomide, and for up to 2 years after stopping. Talk to your doctor if you get pregnant or want to start a family.
  • You have an increased risk of getting an infection while taking leflunomide. Discuss with your doctor.
  • Leflunomide affects your immune system. Before you start and while you are using it, check with your doctor what vaccines you might need. You should not have a live vaccine while using it.
  • You will need regular blood tests while taking leflunomide to check if it is causing problems with your liver or blood.
  • Limit alcohol intake while taking leflunomide. Alcohol may increase the risk of liver problems.
  • It is important to tell anyone who gives you medical or dental treatment that you are taking leflunomide.
  • You may not notice the effects of leflunomide straight away – it can take several weeks before you start to feel better.

This leaflet contains important, but not all, information about this medicine.

Prepared by the PILs Committee at Christchurch Hospital, Canterbury District Health Board, New Zealand. September 2021

For more general information about this sheet annd its contents, see: What does a My Medicines sheet cover?

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About My Medicines

My Medicines Patient Information Leaflets (PILs) contain important, but not all, information about the medicines they describe.

For more information about the sheets, see: What does a My Medicines sheet cover?

My Medicines is developed by a team at the Canterbury District Health Board. Our team is made up of doctors, pharmacists, and a non-medical person to help us keep to plain language. We also discuss our information with specialist health professionals or groups when needed