Leflunomide (Arava) is a drug approved to treat adult moderate to severe rheumatoid arthritis along with other rheumatic diseases. It belongs to a class of medications called disease-modifying antirheumatic drugs (DMARDs), which aim to decrease inflammation and permanent damage.
Leflunomide blocks the formation of DNA, which is important for replicating cells, such as those in the immune system. It suppresses the immune system to reduce inflammation that causes pain and swelling in rheumatoid arthritis.
Leflunomide usually is given as a 20 mg tablet once a day. Sometimes, patients are given only 10 mg, especially if they experienced side effects with the higher dose. Doctors will often 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 100mg (or five 20 mg tablets) once weekly for 3 weeks or 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 should 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.
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 rheumatology provider.
The most common side effect of leflunomide is diarrhea, which occurs in approximately 20% 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, and hair loss. In fewer than 10% 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 can cause serious birth defects. If you are pregnant or are considering having a child, you should discuss this issue with your rheumatology provider before beginning the medication. For this reason, it usually is not prescribed to young women. Breastfeeding 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 rheumatology provider about how to discontinue the medication. Cholestyramine is a medication you can take to help remove leflunomide from your system.
Be sure to tell your rheumatology provider 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). Any medications that can affect the liver should be used with caution with leflunomide.
Live vaccinations should be avoided while taking this medication. Be sure to discuss any vaccines with your rheumatology provider before receiving them. It may be important to receive certain vaccines before starting this medication, such as the Pneumovax (pneumonia vaccine), hepatitis B, or the tetanus booster for some patients.
Because this medication can lower your immunity, it is important you discuss this with any provider treating you for an infection, as this may lead to a different evaluation or treatment. Also, be sure to notify your provider 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.
Updated February 2022 by Bhakti Shah, 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.