Leflunomide (Arava)

Pill Bottle with Pills

Fast Facts

  • Leflunomide is often used to treat rheumatoid arthritis if other DMARDs, such as methotrexate, are not properly controlling symptoms.
  • Leflunomide can cause liver injury, so alcohol and certain other medications should be avoided while on Leflunomide. Blood work should be performed regularly by your rheumatologist to monitor liver function.
  • Leflunomide is often not prescribed to young women, because it can cause serious birth defects and can remain in the body long after the drug is discontinued.

Leflunomide (Arava) is a drug used approved to treat adult moderate to severe rheumatoid arthritis. It belongs to a class of medications called disease-modifying antirheumatic drugs (DMARDs). This class of medicines can decrease joint damage and disability caused by rheumatoid arthritis.

Leflunomide blocks the formation of deoxyribonucleic acid (also known as DNA), which is important for developing cells, such as those in the immune system. It suppresses your immune system to reduce inflammation that causes pain and swelling in rheumatoid arthritis. However, it is not completely clear how this medication works in rheumatoid arthritis.


Leflunomide is used to treat the symptoms of rheumatoid arthritis. It is typically prescribed alone. The effects of using Leflunomide in combination with other DMARDs, such as methotrexate, have not been adequately studied. It is also is used to treat psoriatic arthritis, but the safety data has been largely borrowed from the rheumatoid arthritis studies. There are only limited studies examining the effect of Leflunomide in psoriatic arthritis and polyarticualr juvenile rheumatoid arthritis.

Dosing and time to effect

Leflunomide usually is given as a 20-milligram (mg) tablet once a day. Sometimes patients are given only 10 mg, especially if they experienced side effects with the higher dose. Doctors often will prescribe a “loading dose” to be taken when the medicine is first prescribed. A loading dose is sometimes given for medicines that take a long time to build up in the body. The loading dose of leflunomide is usually 100 mg (or five 20 mg tablets) once weekly for 3 weeks in addition to the regular daily dose. Other times doctors may prescribe a loading dose of 100 mg a day for the first 3 days after starting leflunomide. The loading dose increases a patient’s chances of experiencing diarrhea, but this side effect usually improves after completing the loading dose. Leflunomide probably should probably be taken with food.

It may take several weeks after starting leflunomide to experience an improvement in joint pain or swelling. Complete benefits may not be experienced until 6-12 weeks after starting the medication.

Side Effects

The most common side effect of leflunomide is diarrhea, which occurs in approximately 20 percent of patients. This symptom frequently improves with time or by taking a medication to prevent diarrhea. If diarrhea persists, the dose of leflunomide may need to be reduced.

Less common side effects include nausea, stomach pain, indigestion, rash or hair loss. In fewer than 10 percent of patients, leflunomide can cause abnormal liver function tests or decreased blood cell or platelet counts. Rarely, this drug may cause lung problems such as cough, shortness of breath or lung injury.

Leflunomide lowers your body’s ability to fight off some infections. If you come down with an infection while on Leflunomide, it is important you discuss this with any physician treating you for an infection, as this may lead to a different evaluation or treatment.

It is important that you have regular blood tests, including those for liver function, while taking this medication. You should not take leflunomide if you have a pre-existing liver disease such as hepatitis or cirrhosis. Because alcohol may increase the risk of liver damage from leflunomide, alcohol should be avoided. Any alcohol use should be discussed with your doctor.

Leflunomide can cause serious birth defects. If you are pregnant or are considering having a child, you should discuss this issue with your doctor before beginning this medication. For this reason, it is not often prescribed to young women. Breast-feeding while taking leflunomide is not recommended. Use of an effective form of birth control is critical throughout the course of this treatment and for up to two years after it is stopped. This is important, because leflunomide lasts in the body a long time, even after stopping the medication, and could still cause birth defects during this time. Men taking leflunomide who wish to have a child also should talk with their physicians about how to discontinue the medication. Cholestyramine is a medication you can take to help remove leflunomide from your system.

Drug Interactions

Be sure to tell your doctor about all of the medications you are taking, including over-the-counter drugs and natural remedies, as these may reduce the effectiveness of leflunomide. The following medications are among those that may interfere with leflunomide: cholestyramine (Questran), tolbutamide (Orinase), and rifampin (Rifadin or Rimactane). There are many other drug interactions, and any medication that can affect the liver should be used with caution with leflunomide.

Information to discuss with healthcare providers

Be sure to notify your other physicians that you are taking this drug. Women taking this medication should discuss appropriate forms of birth control with their primary care physician or gynecologist. It is especially important that women discuss the use of this medicine (even past use) with their obstetrician/gynecologist.

Live vaccinations should be avoided while taking this medication. Be sure to discuss any vaccines with your doctor before receiving them. It may be important to receive certain vaccines before starting this medication, such as the Pneumovax (pneumonia vaccine), hepatitis B, tetanus booster, or the Zostavax (shingles vaccine) for some patients.

Because this medication can lower your immunity, it is important you discuss this with any physician treating you for an infection, as this may lead to a different evaluation or treatment. Also, be sure to notify your doctor before any surgeries while taking this medication as Leflunomide can increase the risk of post-operative infections and/or slow the healing of your wounds.

The risk of liver injury may be increased if leflunomide is combined with other medications. Be sure to discuss this with other physicians when new medications are prescribed.

Updated May 2015. Written by Michael Cannon, MD, and reviewed by the American College of Rheumatology Committee on Communications and Marketing. This information is provided for general education only.

Individuals should consult a qualified health care provider for professional medical advice, diagnosis and treatment of a medical or health condition.

© 2015 American College of Rheumatology