Table of Contents
- What is Leflunomide?
- Conditions Treated with Leflunomide
- How Leflunomide Works
- How Leflunomide is Administered
- Potential Side Effects
- Ongoing Research and Potential New Uses
- Precautions and Considerations
What is Leflunomide?
Leflunomide is a medication primarily used to treat certain autoimmune conditions. It’s known by several names, including its brand name Arava and the research code SU101[1]. Leflunomide belongs to a class of drugs called disease-modifying antirheumatic drugs (DMARDs), which work by reducing inflammation and slowing down the progression of certain diseases[2].
Conditions Treated with Leflunomide
Leflunomide is approved and used for treating several conditions:
- Rheumatoid Arthritis: This is a chronic inflammatory disorder affecting the joints[2].
- Psoriatic Arthritis: A form of arthritis that affects some people with psoriasis[3].
- Juvenile Idiopathic Arthritis: A type of arthritis that affects children[4].
Additionally, researchers are exploring its potential use in other conditions, which we’ll discuss later in this article.
How Leflunomide Works
Leflunomide works by inhibiting an enzyme called dihydroorotate dehydrogenase (DHODH). This enzyme is important for the rapid growth of certain cells, including some that are involved in inflammation. By blocking this enzyme, leflunomide can help reduce inflammation and slow down the progression of diseases like rheumatoid arthritis[5].
In the body, leflunomide is converted to its active form called teriflunomide. This active form is responsible for the therapeutic effects of the medication[6].
How Leflunomide is Administered
Leflunomide is typically taken orally (by mouth) as a tablet. The dosage can vary depending on the condition being treated and the patient’s response to the medication. Here are some common dosing regimens:
- For adults with rheumatoid arthritis: Usually started with a loading dose of 100 mg daily for 3 days, followed by a maintenance dose of 20 mg daily[7].
- For children with juvenile idiopathic arthritis: The dose is based on the child’s weight. For example, children weighing less than 20 kg might take 10 mg every other day, while those weighing more than 40 kg might take 20 mg daily[4].
It’s important to note that your doctor will determine the right dosage for you based on your specific condition and needs.
Potential Side Effects
Like all medications, leflunomide can cause side effects. Common side effects may include:
- Diarrhea
- Nausea
- Headache
- Rash
- Elevated liver enzymes
More serious side effects can occur, though they are less common. These may include liver problems, blood disorders, and an increased risk of infections. Your doctor will monitor you closely while you’re taking leflunomide to watch for any potential side effects[3].
Ongoing Research and Potential New Uses
Researchers are exploring the potential use of leflunomide in several other conditions:
- Cancer Treatment: Studies are investigating leflunomide’s potential in treating certain types of cancer, including triple-negative breast cancer and lymphomas[5][1].
- Chronic Graft Versus Host Disease: This is a complication that can occur after bone marrow transplantation[6].
- COVID-19: Some researchers have explored leflunomide’s potential antiviral effects against the virus that causes COVID-19[8].
- Henoch-Schonlein Purpura: A condition that involves swelling of small blood vessels and can cause a skin rash and other symptoms[9].
It’s important to note that these are areas of ongoing research, and leflunomide is not yet approved for treating these conditions.
Precautions and Considerations
Leflunomide requires careful monitoring by your healthcare provider. Here are some important considerations:
- Liver Function: Regular blood tests are needed to monitor liver function while taking leflunomide[3].
- Pregnancy: Leflunomide can cause harm to an unborn baby. Women of childbearing age should use effective contraception while taking this medication and for some time after stopping it[3].
- Infections: Leflunomide can increase the risk of infections. Tell your doctor if you develop signs of an infection while taking this medication[6].
- Vaccinations: Live vaccines should be avoided while taking leflunomide. Discuss any planned vaccinations with your doctor.
Always take leflunomide exactly as prescribed by your doctor, and don’t hesitate to ask questions or report any side effects you experience.


