Leflunomide

Why Do I Need This Treatment?

In conditions such as rheumatoid arthritis and psoriatic arthritis, the immune system becomes overactive.
Instead of protecting you, your white blood cells attack your own joints and skin, leading to pain, swelling, and long-term damage.

To prevent this, doctors use immune-suppressing medicines. Leflunomide is one of the most commonly used of these drugs.

What is Leflunomide and How Does It Work?

Leflunomide is a disease-modifying antirheumatic drug (DMARD).
It blocks the production of certain immune cells that drive inflammation and damage.
By calming the immune system, it reduces symptoms and prevents joint damage.
It is taken as a daily tablet (unlike methotrexate, which is weekly).

Leflunomide Dosing

In Sri Lanka, leflunomide is available in 10 mg tablets.
Treatment usually begins with 10 mg once daily, and then is increased to 20 mg once daily as tolerated.
Tablets must be swallowed whole, not cut, crushed, or chewed. They may be taken with or without food.
Your doctor may adjust the dose depending on blood tests, blood pressure, and side effects.

When Will I Notice Benefits?

Leflunomide may take 4–8 weeks before improvement is noticed.
The full effect may take up to 26 weeks (6 months).
During this period, your doctor may prescribe steroids (e.g., prednisolone) to control inflammation.
Steroids are usually reduced or stopped once leflunomide is working.

Taking Leflunomide Safely

Take exactly as prescribed, usually once daily.
Do not stop or change the dose without medical advice.
Always show your leflunomide prescription to other doctors or pharmacists before starting new medicines.

Possible Side Effects

Common but Usually Mild:

Diarrhea, stomach upset
Nausea
Mild hair thinning
Skin rash

Less Common but Important: stop drug and inform your doctor immediately

Infections may occur more easily (fever, cough, wounds, urinary symptoms)
Blood pressure may rise — close monitoring is required
Severe mouth ulcers or skin rash

If you notice any of the above or fever, persistent cough, severe tiredness, breathlessness, or uncontrolled high blood pressure, stop leflunomide and contact your doctor immediately.

The Importance of Blood Checks

When you are on leflunomide, regular blood tests are absolutely essential.
These blood checks are done to:
- Ensure you are not developing side effects (by monitoring blood counts, liver, and kidney function).
- Ensure the medicine is working effectively (by checking that your disease activity is adequately controlled).
Without both of these, there are risks:
- If monitoring is missed, dangerous side effects may go unnoticed.
- If disease activity is not checked, joint damage can continue silently.

Never continue leflunomide without regular blood tests and follow-up with your rheumatologist.

Monitoring and Safety Checks

Regular blood tests are needed to check:
- Blood counts
- Liver function
- Kidney function
Blood pressure must be monitored regularly.
Avoid or limit alcohol, as it stresses the liver.
Pregnancy planning: Leflunomide remains in the body for a long time.
- Both men and women should avoid pregnancy for at least 2 years after stopping leflunomide, unless a special washout treatment (cholestyramine) is given.
- Do not take leflunomide while breastfeeding.

Combination with Other Medicines

Leflunomide may be used alone or together with:
- Methotrexate or other DMARDs
- Biologic DMARDs
- Steroids (prednisolone tablets or injections)
- NSAIDs (naproxen, ibuprofen)

Long-Term Use

Many patients take leflunomide safely for 10 years or more.
Regular follow-up visits with your rheumatologist are important to monitor effectiveness and side effects.
Some patients may go into remission, while others may need adjustments or changes in therapy.

Key Reminders

Take daily as prescribed – usually 10 mg increasing to 20 mg.
It may take 1–6 months to feel the full benefit. Steroids may be needed at the start.
Stop leflunomide and call your doctor if you develop serious side effects (infections, ulcers, severe rash, uncontrolled high blood pressure).
Regular blood tests and blood pressure checks are essential.
Pregnancy must be deferred for 2 years after stopping leflunomide, unless a washout treatment is given.
Continue treatment long term if effective and safe – do not stop suddenly.
Always show your prescription to any other healthcare provider.

Further Information

For more details, see the Australian Rheumatology Association (ARA) patient information leaflet on Leflunomide:

Leflunomide is an effective long-term treatment for rheumatoid arthritis and psoriatic arthritis when used carefully. It reduces inflammation, prevents joint damage, and helps you maintain a better quality of life — but only if taken with proper blood monitoring and regular follow-up.