A disease-modifying medicine for rheumatoid and psoriatic arthritis
Leflunomide
A disease-modifying medicine for inflammatory arthritis that is harmful in pregnancy and needs blood-pressure and liver monitoring.
What is Leflunomide?
Leflunomide is a disease-modifying anti-rheumatic drug (DMARD) used for rheumatoid and psoriatic arthritis. It calms the overactive immune response that damages joints. It stays in the body for a long time, is harmful in pregnancy and needs a special "washout" if pregnancy is planned, and requires regular blood-pressure, liver and blood-count monitoring.
Education and reference only. This is a plain-language guide to Leflunomide — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Leflunomide is a long-term medicine used to control rheumatoid arthritis and psoriatic arthritis. As a disease-modifying drug, it works on the underlying disease to slow joint damage rather than only easing symptoms. It is taken regularly, builds its effect over several weeks, and is usually managed alongside a specialist rheumatology team.
How it works
Leflunomide blocks an enzyme that immune cells need to multiply, which dampens the overactive immune response driving inflammation in the joints. By calming this process, it reduces joint pain and swelling and helps protect the joints from longer-term damage. Because it acts on the disease itself, the benefit develops gradually over weeks.
Company & origin
Originated / developed by: Hoechst Marion Roussel (originator).
An immune-modulating DMARD introduced in the late 1990s for rheumatoid and psoriatic arthritis.
What it treats
Conditions Leflunomide is used for
Practical use
How to take Leflunomide
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it at the same time each day, with or without food.
- Use reliable contraception throughout and discuss any pregnancy plans well in advance.
- Keep taking it regularly, as the benefit builds over several weeks.
- Keep up with your blood-pressure checks and blood tests, and limit alcohol.
- If you miss a dose, take it when you remember unless it is nearly time for the next one — do not double up.
Weighing it up
Advantages & disadvantages of Leflunomide
Advantages
- An effective disease-modifying option that slows joint damage.
- A useful alternative when methotrexate is unsuitable or not enough.
- Can be combined with other arthritis treatments under specialist care.
Disadvantages
- Harmful in pregnancy and lingers in the body, needing a washout to remove it.
- Can raise blood pressure and affect the liver and blood count.
- Requires regular monitoring and limits on alcohol.
Practical use
Good to know
Leflunomide is harmful to an unborn baby, so reliable contraception is essential, and it must be stopped — usually with a special "washout" procedure using another medicine — before trying for a baby, because it lingers in the body for a long time. It can raise blood pressure and affect the liver and blood count, so blood pressure and blood tests are checked regularly. Report any signs of infection, persistent diarrhoea, breathlessness or yellowing of the skin. Alcohol should be limited because of the liver effects.
Who should not take it / use with caution
- Women who are pregnant, breastfeeding or planning pregnancy without a washout, and men hoping to father a child without first discussing a washout with their specialist (the medicine passes into semen).
- People with significant liver disease, serious infection or a weakened immune system.
- People with severe low blood counts or uncontrolled high blood pressure.
Monitoring
- Blood pressure, checked regularly during treatment.
- Liver function and full blood count (blood tests) at intervals.
- Signs of infection, breathlessness or persistent diarrhoea to report promptly.
Side effects
- Diarrhoea, nausea, headache or hair thinning.
- Raised blood pressure and changes in liver blood tests.
- Less commonly, low blood counts, infections or breathing problems — report fever, breathlessness or yellowing of the skin.
Key interactions
- Combining it with other liver-affecting or immune-suppressing medicines needs care.
- Live vaccines are generally avoided while taking it.
- It can raise levels of some other medicines, and certain treatments (such as cholestyramine) are used to wash it out.
Available as: Tablets.
Answers
Leflunomide: frequently asked questions
Can I take leflunomide if I might become pregnant?
No — leflunomide can harm an unborn baby, so reliable contraception is essential while taking it. Because it stays in the body for a long time, a special washout procedure is needed before trying for a baby. Discuss any pregnancy plans with your specialist well in advance.
Why do I need my blood pressure checked on leflunomide?
Leflunomide can raise blood pressure in some people. Regular checks make sure any rise is picked up and managed. Tell your team if you have headaches or other symptoms, and keep your monitoring appointments.
What is a leflunomide "washout"?
Because leflunomide lingers in the body for many months, a washout uses another medicine (such as cholestyramine) to clear it more quickly. This is done if you are planning pregnancy, have a serious side effect, or need to remove the drug rapidly.
Can I drink alcohol with leflunomide?
It is best to limit alcohol because both alcohol and leflunomide can affect the liver, and together they raise the risk of liver problems. Your liver blood tests are monitored; follow your team's advice on safe limits.
How long does leflunomide take to work?
As it acts on the underlying disease, it usually takes several weeks to show its full benefit in arthritis. Keep taking it regularly even if you do not notice an improvement straight away, and stay in touch with your team.
The wider class
About Disease-modifying anti-rheumatic drugs (DMARDs)
Leflunomide belongs to the disease-modifying anti-rheumatic drugs (dmards) class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF
- NICE CKS
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