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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.

Before you start

  • Tell your doctor if you have liver, lung or blood pressure problems.
  • 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.
  • Leflunomide weakens your immune system, making it harder for your body to fight infections. You may need tests before you start to make sure you don't have any infections like tuberculosis (TB), HIV, or hepatitis B and C.
  • Ask your doctor what vaccines you might need before you start and while you are taking leflunomide. You should not have a live vaccine while taking leflunomide.

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:

  • You will need regular blood tests while taking leflunomide to check if it is causing problems with your liver or blood.
  • Protect yourself from too much sunlight while taking immunosuppressant medicines (they may increase your risk of skin cancer). Always cover up and apply a thick layer of broad spectrum sunscreen (at least SPF30) when outside. Do not use sunbeds.
  • Women using leflunomide for a long time may need cervical screening more often. Discuss with your doctor.
  • It is important to tell anyone who gives you medical or dental treatment that you are taking leflunomide.
  • Limit alcohol intake while taking leflunomide. Alcohol may increase the risk of liver problems.
  • 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 MyMedicines Committee at Christchurch Hospital, Te Whatu Ora - Waitaha, New Zealand. March 2023

For more general information about this sheet and 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 Te Whatu Ora – Waitaha. 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